Saturday

April 25, 2015

April 25, 2015

Number of results: 8,705

**statistics**

Employees in a large computer firm claim that the mean salary of the firm’s programmers is less than that of its competitors. The competitor’s salary is $47,000. A random sample of 30 of the firm’s programmers has a mean salary of $46,500 with a standard deviation of 5500. ...
*June 6, 2011 by Eric*

**Statistics**

Employees in a large computer firm claim that the mean salary of the firm’s programmers is less than that of its competitors. The competitor’s salary is $47,000. A random sample of 30 of the firm’s programmers has a mean salary of $46,500 with a standard deviation of 5500. ...
*June 7, 2011 by Kelly*

**statistics**

Employees in a large computer firm claim that the mean salary of the firm’s programmers is less than that of its competitors. The competitor’s salary is $47,000. A random sample of 30 of the firm’s programmers has a mean salary of $46,500 with a standard deviation of 5500. ...
*June 14, 2011 by Shawnie*

**statistics**

The diameters of apples in a certain orchard are normally distributed with a mean of 4.77 inches and a standard deviation of 0.43 inches. Show all work. (A) What percentage of the apples in this orchard is larger than 4.71 inches? (B) A random sample of 100 apples is gathered ...
*September 2, 2011 by Laynette*

**math**

Empirical rule the authors generac generator produces voltage amounts with a mean of 125.0 volts and a standard deviation of 0.3 volt,and the voltage have a bell-shape distribution.using the empirical rule,what is the approximate percentage of voltage amounts between 124.4 ...
*September 18, 2011 by bibi*

**Statistics**

Olive-Oil producers have expanded to approximately 120 producers statewide. Analysts estimate the average price consumers pay for a bottle of olive oil is $21, with a standard deviation of $2.40. What is the probability that the average price paid by a random sample of 36 ...
*November 17, 2011 by Amber*

**Math**

You invent a new system to make excellent racing tires for the Indianapolis 500/ Your tires are good for an average of 105 miles, with a standard deviation of 7.5 miles. What is the probability that one of your tires can go for at least 44 laps? What is the probability that ...
*July 10, 2012 by Lindsey*

**statistics**

The diameters of grapefruits in a certain orchard are normally distributed with a mean of 6.45 inches and a standard deviation of 0.45 inches. Show all work. (A) What percentage of the grapefruits in this orchard have diameters less than 7.1 inches? (B) What percentage of the ...
*August 28, 2011 by Laynette*

**Statistics**

Assume the body temperature of healthy adults are normally distributed with a mean of 98.2F and a standard deviation of 0.62F. If you have a body temperature of 99.00F, what is your percentile score? Convert 99.00F to a standard score(or a z-score). Is a body temprature of 99....
*August 19, 2010 by Lindsy*

**Statistics**

Suppose that the average grade for all people who take this course in statistics is 83 with a standard deviation of 3.5. If your particular class has an average of 89, can you conclude that your class is better than average at the 90 percent confidence level? Identify one or ...
*November 15, 2009 by Terra*

**Hypothesis**

Suppose that the average grade for all people who take this course in statistics is 83 with a standard deviation of 3.5. If your particular class has an average of 89, can you conclude that your class is better than average at the 90 percent confidence level? Identify one or ...
*November 16, 2009 by Terra*

**statistics**

5. A soft drink dispensing machine uses paper cups that hold a maximum of 12 ounces. The machine is set to dispense a mean of 10 ounces of the drink. The amount that is actually dispensed varies. It is normally distributed with a standard deviation of one ounce. (a) What ...
*September 15, 2014 by Sarah *

**stats**

A physical fitness association is including the mile run in its secondary-school fitness test. The time for this event for boys in secondary school is known to possess a normal distribution with a mean of 460 seconds and a standard deviation of 50 seconds. Between what times ...
*November 4, 2014 by elenore*

**statistics**

According to a study of 90 truckers, a trucker drives, on average, 540 miles per day. If the standard deviation of the miles driven per day for the population of truckers is 40, find the 99% confidence interval of the mean number of miles driven per day by all truckers.
*April 13, 2010 by Anonymous*

**RES 341**

A sample of 300 is taken and the sample mean is computed to be 7.65 and the sample standard deviation is 5. Assume the data is ratio level. Compute the 95% confidence interval on the mean. Compute the 3.9% confidence interval on the mean Which confidence interval is more ...
*October 16, 2010 by Meh*

**statistics**

Listed below are the duration's (in hours) of a simple random sample of all flights of a space shuttle program. Find the range, variance, and standard deviation for the sample data. Is the lowest duration time unusual? Why or why not? 71, 100, 237, 199, 164, 269, 193, 379, 252...
*February 13, 2015 by slomo*

**math**

Express Courier Service has found that the delivery time for packages is normally distributed with mean 14 hours and standard deviation 2 hours. What should be the guaranteed delivery time on all packages in order to be 95% sure that the package will be delivered before this ...
*January 21, 2013 by Jessica*

**statistics**

In performing a hypothesis test, the null hypothesis is population mean = 6.9 and the alternative hypothesis is population mean ≠ 6.9, a random sample of 16 items is selected. The sample mean is 7.1 and the sample standard deviation is 2.0. The population is ...
*August 17, 2014 by Anonymous*

**Statistics**

In a survey, the guess at the mean age for the class had a mean of 21.9 and a standard deviation of 3.03. Given that Normally distributed populations have a first quartile of Z=-0.67 and a third quartile of Z=.67, what does this suggest about whether or not these guesses are ...
*July 14, 2011 by david*

**statistics**

An accounting firm is planning for the next tax preparation season. From last year's returns, the firm collects a systematic random sample of 100 filings. The 100 filings showed an average preparation time of 90 minutes with a standard deviation of 140 minutes. What is the ...
*November 19, 2011 by SHA*

**math**

A bank wishing to determine the average amount of time a customer must wait to be served took a random sample of 100 customers and found that the mean waiting time was 7.2 minutes. Assuming that the population standard deviation is known to be 15 minutes, find the 90% ...
*May 22, 2014 by Anonymous*

**Math**

A random survey of 500 households determines that 20% of the households would do so and that each participating household expects to recycle about 100 cans monthly with a standard deviation of 30 cans. Question (a) What is the 95% confidence interval regarding the percentage ...
*April 21, 2010 by Jamie*

**Statistics**

The international Coffee Association has reported the mean daily coffee consumption for U.S. residents as 1.65 cups. Assume that a sample of 38 people from a North Carolina city consumed a mean of 1.84 cups of coffee per day, with a standard deviation of 0.85 cups. In a two-...
*June 4, 2010 by Julia Brown*

**Statistics**

You are getting ready to take a sample from a large population, and need to determine the appropriate sample size. You are estimating sales at a large chain of department stores. A previous survey from the same population found a standard deviation of $18. What sample size is ...
*July 16, 2012 by Devika*

**Statistic**

Assume that a population is normally distributed with a mean of 100 and a standard deviation of 15. Would it be unusual for the mean of a sample of 3 to be 115 or more? Why or why not? What if the size for each sample was increased to 20? Would a sample mean of 115 or more be ...
*June 9, 2013 by Berry*

**Statistics/Probability**

The life span of a calculator has a normal distribution with a mean of 60 months and a standard deviation of 5 months. If a calculator is randomly selected, find the probability that the calculator has a life span of. (1) more than 50 months (2) between 4 years and 6 years.
*July 10, 2014 by Heidi*

**microbiology**

can anyone help me to figure out how to work out STANDARD DEVEATION CALCULATIONS please? Do you have a specific example? There are formulas for standard deviation you can use if you are expected to do the calculations by hand. You can also use calculators or statistical ...
*April 29, 2007 by nicky*

**Stats**

Suppose the following data are selected randomly from a population of normally distributed values. 42 51 43 48 41 57 54 39 45 48 45 39 46 Construct a 95% confidence interval to estimate the population mean. Round the intermediate values to 2 decimal places. Round your answers ...
*December 19, 2013 by Tyler*

**statistics**

Select which of the following are examples of parameters from these examples. Question options: The probability that a ticket with be a winner is .2 (or a 20% chance) The proportion of winning tickets in the sample of 100 99% of samples will have between 37% and 43% of voters ...
*June 29, 2014 by Anonymous*

**statistics**

the scheduled commuting time on Long Island Rail Road from Glen Cove to New York is 65 minutes. Suppose that the actual commuting time is uniformly distributed between 64 and 74 minutes. What is the probability that the commuting time will be a) less than 70 minutes B) between...
*January 11, 2011 by ann*

**Elementary Statistics help**

It is generally believed that electrical problems affect about 14% of new cars. An automobile mechanic conducts diagnostic tests on 128 new cars on the lot. a. Describe the sampling distribution for sample proportion by naming the model and telling its mean and standard ...
*October 29, 2007 by LT*

**statistics**

a large study involving over 20000 individuals shows that the mean percentage intake of kilocalories from fat was 39% with a range from 6%- 72%. a small sample study was conductd to determine if the mean intake of patiens was different from 39%. a sample of 15 patients had a ...
*December 15, 2012 by phiney*

**Chem**

Can someone explain the difference or how to tell between internal/external standard, standard addition and how it relates calibration standards?
*December 13, 2011 by Ano*

**chemistry**

Is deltaH standard of TdeltaS standard more important in determining whether KHT will be soluble in water at a given temperature?
*February 25, 2014 by Gracie*

**statistics**

The time required by workers to complete an assembly job has a mean of 50 minutes and a standard deviation of 8 minutes. To spot check the workers' progress on a particular day, their supervisor intends to record the times 60 workers take to complete one assembly job apiece. ...
*March 8, 2012 by Gift*

**Biostatistics HW**

Consider again the data in problem #6. Suppose that in the aerobic exercise group we also measured the number of hours of aerobic exercise per week and the mean is 5.2 hours with a standard deviation of 2.1 hours. The sample correlation is -0.42. Exercise Group N Mean Std Dev ...
*May 22, 2012 by Anonymous*

**Statistics**

Suppose the mean income of 35-year-olds in the U.S. is $25,000. A random sample of 150 35-year-olds in California results in a sample mean income of $26,600 and a sample standard deviation of $3800. At the 5% significance level, can we conclude that the true mean income of 35-...
*April 26, 2011 by Erinn*

**Math**

Maria is playing a game of chance at the Hibiscus festival, costing $1 for each game. In the game two fair dice are rolled and the sum of the numbers that turn up is found. If the sum is seven, then Maria wins $5. Otherwise Maria loses her money. a) Construct Maria’s ...
*April 19, 2012 by Koia*

**statistic**

a restaurant that bills its house account monthly is concerned that the average monthly bill exceeds $200 per account. A random sample of twelve account is selected, resulting in a sample mean of $220 and a standard deviation of $12. Use a= 0.05. what is the critical value for...
*December 11, 2012 by HN*

**Maths *have answer, want method* Urgent!**

Suppose that the blood pressure of the human inhabitants of a certain Pacific island is distributed with mean, \mu = 108 mmHg and standard deviation , \sigma = 6 mmHg. According to Chebyshev's Theorem, at least what percentage of the islanders have blood pressure in the range ...
*April 13, 2013 by Orla*

**Math**

8) A consumer groups tries to determine the most expensive items in a convenience store. Four items are purchased in the convenience store and compared to the average price in stores in the area. Assume tat the price distribution is normal. Use your calculator to determine the...
*November 18, 2012 by Kay*

**Math Need Help. No Idea how to solve**

A medical researcher is interested in the prenatal care received by pregnant women in inner cities. She interviews 35 randomly selected women with children on the streets of Baltimore and finds that the average number of gynecological checkups per pregnancy was 3, with a ...
*October 8, 2014 by Anonymous*

**Chemistry**

I conducted a Gas Chromatography experiment using Flame Ionisation Detector (FID).A capillary column was used. 1)Blank 2) Standard 3) Sample 4)Blank 5)Standard The above was injected into the system. In 2)Standard chromatogram,a sharp, thin peak was observed between the 2 ...
*February 18, 2012 by mandy*

**statistics**

A survey is being planned to determine the mean amount of time corporation executives watch television. A pilot survey indicated that the mean time per week is 15 hours, with a standard deviation of 3.5 hours. It is desired to estimate the mean viewing time within one-quarter ...
*October 30, 2011 by Nathalia*

**statistics**

an auditor wishes to test the assumption that the mean value of all accounts receivable in a given firm is $260.00 she will reject this claim only if it is clearly contradicted by the sample mean. the sample standard deviation of 36 accounts is $43, the sample mean is $250, ...
*April 29, 2012 by b*

**Math**

Suppose the average size (in square feet) of homes in a certain region is 1747. Assume the variable is normally distributed with standard deviation 220. If a person in the region was intending to build a 1890 square foot home but downsized and built a 1274 square foot home, ...
*July 12, 2014 by Shelagh*

**bus stats**

Given the following information about a hypothesis test of the difference between two means based on independent random samples, what is the standard deviation of the difference between the two means? Assume that the samples are obtained from normally distributed populations ...
*June 23, 2011 by jenny*

**statistics**

a manufacturer of detergent claims that the contents of the boxes in the market weigh on average at least 16 oz.. the distribution of weights is known to be normal with a standard deviation of 0.4 oz. to test the claim of the manufacturer a random sample of 16 boxes were ...
*May 28, 2012 by sayera*

**statistics**

a manufacturer of detergent claims that the contents of the boxes in the market weigh on average at least 16 oz.. the distribution of weights is known to be normal with a standard deviation of 0.4 oz. to test the claim of the manufacturer a random sample of 16 boxes were ...
*May 28, 2012 by sayera*

**statistics**

President Obama wants to provide aid to people who are having a rough time. Year 2007 $13,182 (mean salary) = x bar $3,550 = standard deviation President Obama wants to give money to the lowest 15% from the rest of the population. What income level will receive the stimulus ...
*July 2, 2009 by Bulldog 42*

**Statistics**

An auditor reviewed 25 oral surgery insurance claims from a particular surgical office, determining that the mean out-of-pocket patient billing above the reimbursed amount was $275.66 with a standard deviation of $78.11. (a) At the 5 percent level of significance, does this ...
*June 6, 2010 by Robert*

**Stats**

An auditor reviewed 25 oral surgery insurance claims from a particular surgical office, determining that the mean out-of-pocket patient billing above the reimbursed amount was $275.66 with a standard deviation of $78.11. (a) At the 5 percent level of significance, does this ...
*November 3, 2010 by Sami*

**MATH**

Battery Power Problem. A certain type of thermal battery for an airplane navigation device backup power has a mean life of 300 hours with a standard deviation of 15 hours. What proportion of these batteries can be expected to have lives of 322 hours or less? Assume a normal ...
*April 1, 2010 by Ty*

**statistics**

Based on a random sample of 25 units of lawnmowers, the average weight is 102 lbs., and the sample standard deviation is 10 lbs. We would like to decide if there is enough evidence to establish that the average weight for the population of lawnmowers is greater than 100 lbs. ...
*October 5, 2010 by julie*

**Statistics**

Suppose a tire manufacturer wants to set a mileage guarantee on its new XB 70 tire. Life tests revealed that the mean mileage is 47,900 miles and the standard deviation is 2,050. The manufacturer wants to set the guaranteed mileage so that no more than five percent of the ...
*November 24, 2011 by Brea*

**Statistics **

The number of traffic accidents per day on a certain section of highway is thought to be Poisson distributed with a mean equal 2.19. Based on this, how many traffic accidents should be expected during a week long period? a. 15.33 b. 10.95 c. approximately 10.36 d. ...
*October 10, 2012 by Aria*

**Statistics**

According to the American Automobile Association (AAA), the mean cost of a gallon of regular unleaded fuel in 2007 was $2.835. AAA noted that the standard deviation of the fuel price was $0.15. A random sample of n=100 gas stations is selected and the mean gas price is ...
*June 23, 2013 by Jerome*

**math/Check!**

a. An ellipse is formed by stretching the graph of x^2+ y^2=1 horizontally by a factor of 3 and vertically by a factor of 4. Determine the equation of the ellipse in standard form x^2/a^2+y^2/b^2=1 (x/3) ^2+ (y/4) ^2=1 x^2/9 + y^2/16 =1 so the equation is: x^2/9 + y^2/16 =1 b...
*December 4, 2006 by sam!*

**statistics**

Suppose that you got a score of X=78 on an English test for which the mean was (mu)=70 and the standard deviation was (lower case sigma)=10. Also, suppose that you got a scores of X=64 on a Spanish test with mean(mu)=50 and (lower case sigma)=7. For which test would you expect...
*February 4, 2008 by Kat*

**statistics**

The average age of statistics students nationwide is 22. The standard deviation is 2.5 years. Assume the age is a normally distributed variable. Find the probability that one student selected at random is older than 23. Find the probability that the mean age of a group of 16 ...
*June 11, 2010 by DezShonna K*

**college ststistics**

A. find the binomial probability p(x=5) where n=14 and p=0.30. B. setup without solving the binomial probability p(x is at most 5) using probability notation C. how would you find normal approximation to the binomial probability p(x=5) in part A. please show how you would ...
*June 3, 2012 by melba*

**AP Statistics**

When finding a confidence interval for a population mean based on a sample of size 11, which assumption is made? The standard deviation is fixed. The sampling distribution of z is normal. The sampling distribution of the sample means is approximately normal. There is no ...
*October 29, 2012 by Anonymous*

**stats**

Test scores on a university admissions test are normally distributed, with a mean of 500 and a standard deviation of 100. 4 marks a. What is the probability that a randomly selected applicant scores between 425 and 575? 4 marks b. What is the probability that a randomly ...
*June 1, 2013 by sue*

**college statistics**

The mean of a normal distribution is 400 pounds. The standard deviation is 10 pounds. What is the area between 415 pounds and the mean of 400 pounds? The area between the mean and 395?
*March 22, 2009 by brenduh*

**science**

3. In a sample of 64 students given an examination in statistics, it is found that the mean weight is 57 kg with standard deviation 9 kg. Find : ƒÜ i) The proportion of students weight 48-62 kg. ƒÜ ii) The proportion of those less than 72 kg. ƒÜ iii) The proportion of those ...
*February 22, 2013 by suhad*

**business and finite calc **

2) The amount of gasoline sold every week at a gas station is Normally distributed with a mean of 30,000 gallons and a Standard Deviation of 3,000 gallons. What is the Probability that in a given week that the amount of gasoline sold is between 28,000 and 35,000 gallons?
*May 16, 2014 by jeremiah *

**Statistics**

A production process is checked perifically by a quality control inspector. The inspector selects simple random samples of 30 finished products and computes the sample mean product weights x. If test results over a long period of time show that 5% of the x values are over 2.1 ...
*October 30, 2007 by Rebecca*

**Discrete Math**

You have two decks of 26 cards. Each card in each of the two decks has a different letter of the alphabet on it. You pick at random one card from each of the two decks. A vowel is worth 3 points and a consonant is worth 0 points. Let X = the sum of the values of the two cards ...
*November 15, 2011 by Martin*

**statistics**

The times taken to complete a statistics test by all students are normally distributed with a mean of 120 minutes and a standard deviation of 12 minutes. Find the probability that the mean time taken to complete this test by a random sample of 16 students would be between 122 ...
*December 16, 2011 by shasha*

**statistics**

The times taken to complete a statistics test by all students are normally distributed with a mean of 120 minutes and a standard deviation of 12 minutes. Find the probability that the mean time taken to complete this test by a random sample of 16 students would be between 122 ...
*December 16, 2011 by shasha*

**statistics**

random sample of n = 16 scores is selected from a normal distribution with a mean of μ = 50 and standard deviation of σ = 10. a. what is the probability that the sample mean will have a value between 45 and 55? b. what is the probability that the sample mean will ...
*October 15, 2012 by angela*

**MBA**

1- The height of adult women in the United States is normally distributed with mean 64.5 inches and standard deviation 2.4 inches. Find the probability that a randomly chosen woman is (a) Less than 63 inches tall (b) Less than 70 inches tall (c) Between 63 and 70 inches tall (...
*March 25, 2014 by Bunkym*

**Business Statistics**

In a goodness-of-fit test, the null hypothesis states that the data came from a normally distributed population. The researcher estimated the population mean and population standard deviation from a sample of 500 observations. In addition, the researcher used 6 standardized ...
*March 15, 2009 by Stuart*

**statistics**

A study of the amount of time it takes a mechanic to rebuild the transmission for a 1992 Chevrolet Cavalier shows that the mean is 8.4 hours and the standard deviation is 1.77 hours. Assume that a random sample of 40 mechanics is selected and the mean rebuild time of the ...
*April 16, 2015 by phia*

**statistics**

A company wishes to make 1 ounce candy bars. According to government regulations, in order to label the candy bars as 1 ounce, at least 95 % of the bars must weigh 1 ounce or more. Our process standard deviation is .08 ounces. What do we need to make the mean weight be so that...
*October 29, 2014 by Anonymous*

**stats**

A company wishes to make 1 ounce candy bars. According to government regulations, in order to label the candy bars as 1 ounce, at least 95 % of the bars must weigh 1 ounce or more. Our process standard deviation is .08 ounces. What do we need to make the mean weight be so that...
*October 29, 2014 by Alex*

**statistics**

A company wishes to make 1 ounce candy bars. According to government regulations, in order to label the candy bars as 1 ounce, at least 95 % of the bars must weigh 1 ounce or more. Our process standard deviation is .08 ounces. What do we need to make the mean weight be so that...
*October 30, 2014 by Anonymous*

**math (stats)**

For a car traveling 30 mph in normal conditions, the distance required to brake to a stop is normally with a mean of 50 feet and a standard deviation of 8. you are traveling in a area at 30 mph and a car swerves into your path at a distance of 60 feet away. what is the ...
*November 17, 2014 by sarah*

**stats**

A manufacturer of automobile batteries claims that the distribution of battery life is 54 months with a standard deviation of 6 months. We take a random sample of 50 batteries. a. Find the probability that their mean life is less than 52 months. b. Find the probability that ...
*July 31, 2011 by michelle*

**staTS**

A carton of soy milk states on the label that it contains 956 mL. The volume of soy milk in 9 randomly chosen cartons is measured and the mean found to be 958.72 mL. Assume that the cartons are filled so that the actual amounts are normally distributed with a mean of 956 mL ...
*October 10, 2010 by gs*

**jik**

A carton of soy milk states on the label that it contains 956 mL. The volume of soy milk in 9 randomly chosen cartons is measured and the mean found to be 958.72 mL. Assume that the cartons are filled so that the actual amounts are normally distributed with a mean of 956 mL ...
*October 10, 2010 by farita*

**statistics**

A business uses a 7-point scale about satisfaction with the services it provides to clients. The ratings are normally distributed with a mean of 4.8 and a standard deviation of .5. What percentage of clients rate their satisfaction 1) Above 5? 2) Above 6? 3) Above 4? 4) Below ...
*March 24, 2011 by Sarah *

**chemistry**

1. How do you know that NO2 (with a negative charge 1) is an anion and not ionic compound? 2. What are the SI standard units for length and mass? Why ins't there a standard SI unit for volume?
*January 26, 2009 by becca -- got final exam tomorrow help!*

**introduction to health care**

the view that a patient is an independent actor is known as a.social justice b.autonomy c.the subject standard d.the objective standard my answer is a
*November 27, 2013 by susue*

**introduction to health care**

the view that the ppatient is an independent actor is known as a.social justice b.autonomy c.the subjective standard d.the objective standard my answer is d
*December 4, 2013 by susue*

**Chem HELP !!!**

Using a table of standard electrode potentials (as in Appendix M of your text), calculate the standard cell potential, Eo, for: 2 Fe2+(aq) + Cl2(g) 2 Fe3+(aq) + 2 Cl(aq).
*March 16, 2014 by Nancy*

**statistics**

Assume the body temperatures of healthy adults are normally distributed with a mean of 98.20 °F and a standard deviation of 0.62 °F (based on data from the University of Maryland researchers). Is a body temperature of 99.00 °F unusual? Why or why not? Fifty adults are ...
*April 2, 2010 by anonymous*

**MATH Prob.**

Battery Power Problem. A certain type of thermal battery for an airplane navigation device backup power has a mean life of 300 hours with a standard deviation of 15 hours. What proportion of these batteries can be expected to have lives of 322 hours or less? Assume a normal ...
*August 12, 2009 by Twg*

**Teacher Math**

Battery Power Problem. A certain type of thermal battery for an airplane navigation device backup power has a mean life of 300 hours with a standard deviation of 15 hours. What proportion of these batteries can be expected to have lives of 322 hours or less? Assume a normal ...
*March 30, 2010 by Iris*

**statistics**

sample- a recent study reports that older adults who got regular physical exercise experienced fewer symptoms of depression, even when tested 2 years late. regular excersize scores= 1,3,4,3,5,2,3,4 no regular excersize scores=5,4,6,3,5,7,6,6 a)calculate the mean and the ...
*January 30, 2008 by Byron*

**chemistry**

Why are standard KMnO4 solutions are seldom used for the titrations of solutions containing HCl? 2. Why are standard solutions of reductants less often for titrations than standard solutions of oxidants? 3. When a solution of KMnO4 was left standing in a buret for 3 hours, a ...
*May 13, 2009 by angel*

**Statistics**

Suppose that the average grade for all people who take this course in statistics is 83 with a standard deviation of 3.5. If your particular class has an average of 89, can you conclude that your class is better than average at the 90 percent confidence level? Sample size 21. ...
*November 17, 2009 by Terra*

**Statistics**

Assume the wait time to see a cardiologist at a certain clinic are uniformly distributed between 7 minutes and 23 minutes. Calculate the probability a randomly selected patient waits at least 18 minutes to see the cardiologist. The random variable, Z, is associated with a ...
*March 26, 2013 by Bill*

**statistics**

In one history class, 34 students took an exam. The mean of the exam was 52 with a standard deviation of 13. If the instructor is going to assume data are normally distributed and assign grades on a curve, then she will assign an A to the top 10% of the class, B's to the next ...
*November 29, 2010 by melissa*

**statistics**

Please help asap! A tire company is considering a tire replacement company. They have agreed to replace any tire that fails with a life in the bottom 10% of the population. For a given population of tires, the life is a normal distribution with a mean of 27 months and a ...
*January 18, 2011 by Going crazy*

**Math**

What is the approximate percentile rank of a lightbulb that failed at 9000 hours if the number of lightbulbs is 400? The number of lightbulbs that lasted between 5400 and 9000 were about 326 lightbulbs. The mean is 7800 and the standard deviation is 1200 My guess was: ...
*December 5, 2012 by alice*

**stastic**

A can of Coke is supposed to contain, on the average, 16 ounces of soda with a standard deviation of 0.4 ounces. Suspecting fraud, you take a random sample of 50 cans and measure the amount of Coke in each. Your measurements show that the 50 cans had a means 15.9 ounces. What ...
*April 18, 2014 by kima*

**statistics**

If the heights within a certain subpopulation of people are normally distributed with a mean of 180 centimeters and a standard deviation of 10 centimeters, what proportion of the people is shorter than 195 centimeters? Z=(score-mean)/SD after finiding the proportion i looked...
*February 25, 2011 by Crystal*

**statistics**

If the heights within a certain subpopulation of people are normally distributed with a mean of 180 centimeters and a standard deviation of 10 centimeters, what proportion of the people is shorter than 195 centimeters? Z=(score-mean)/SD after finiding the proportion i looked...
*February 25, 2011 by Crystal*

**statistics**

A sample of 106 students, the researchers reported the following statistics...mean= 13.2 s=19.5 Explain why the distribution for these 106 students cannot be symmetric and given this, what % of 106 students fall within the x+/-2s? I understand it cannot be symmetric b/c the ...
*September 13, 2013 by helpthedumbie*