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April 20, 2014

April 20, 2014

**Recent Homework Questions About Statistics**

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**Statistics**

An industrial engineer has found that the standard household light bulbs produced by a certain manufacturer have a useful life that is normally distributed with a mean of 250 hours and a variance of 2500. (a) What is the probability that a randomly selected bulb from this ...
*Tuesday, March 11, 2014 at 10:09am*

**Elementary Statistics**

5*4*3= 60
*Monday, March 10, 2014 at 7:05pm*

**6th grade math - statistics**

Can you explain why Q1 = 3.5 and Q3 is 9 out of this dataset 0, 1, 3, 4, 6, 7, 7, 7, 8, 10, 12, 12. My answers were: Assuming median would be 7 (using numbers in positions 6 and 7 where 7+7/2 = 7) Q1 dataset would be 0,1,3,4,6; Q1 = 3 Q2 dataset would be 7,8,10,12,12; Q3= 10 ...
*Monday, March 10, 2014 at 5:17pm*

**Statistics**

The mean serves as a fulcrum or balance point for a distribution. Therefore the difference from 30 must be the same on both sides. A wide variation of values could fit both situations. However, in the second situation, all scores could be 30.
*Monday, March 10, 2014 at 3:11pm*

**Statistics**

Is that value the Z score or the probability? Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability (.095) and its Z score.
*Monday, March 10, 2014 at 3:00pm*

**statistics**

I'm not sure what you might be asking. Z = (score-mean)/SD Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability related to the Z score.
*Monday, March 10, 2014 at 2:55pm*

**Statistics**

In an experiment, you measure the popularity of two brands of soft drinks (factor A), and for each brand you test males and females (factor B). The following table shows the main effect and cell means from the study: Factor A Level A1: Level A2: Brand X Brand Y Level B1: 14 23...
*Monday, March 10, 2014 at 1:03pm*

**Statistics**

A researcher investigated the effect of volume of background noise on participants’accuracy rates while performing a difficult task. He tested three groups of randomly selected students and obtained the following means and sums of squares: Volume Source Sum of sqs. df ...
*Monday, March 10, 2014 at 11:13am*

**statistics**

assuming that adults have IQ scores that are normally distributed with a mean of 100 and standard deviation of 15. Find the probability that a randomly selected adult has an IQ less than 121.
*Monday, March 10, 2014 at 10:22am*

**statistics**

1. A company decides to add a new program that prepares randomly selected sales personnel to increase their number of sales per month. The mean number of sales per month for the overall population of sales people at this national company is 25 with a standard deviation of 4. ...
*Monday, March 10, 2014 at 1:04am*

**Statistics**

What is 0.095 on the z-score table or where
*Sunday, March 9, 2014 at 8:59pm*

**statistics**

You can plug in your data and play around with it at http://davidmlane.com/hyperstat/z_table.html
*Sunday, March 9, 2014 at 7:12pm*

**statistics**

Assuming that the distribution is normal for weight relative to the ideal and 99% of the male participants scored between (–53.68, 64.64), where did 95% of the values for weight relative to the ideal lie? R
*Sunday, March 9, 2014 at 4:22pm*

**Statistics**

Put in Binomial Probability Formula? probability ( 2 of 22 are lost) = C(22,2) (1/200)^2 (199/200)^20
*Sunday, March 9, 2014 at 6:59am*

**Statistics**

List five numbers for which the sample mean is 30 and not all numbers are equal and would have a mean of 30 but all numbers are equal
*Sunday, March 9, 2014 at 3:24am*

**Statistics**

How do I plug this into the Binomial Probability Formula? prob(lost) = 5/1000 = 1/200 prob(not lost) = 199/200 prob( 2 of 22 are lost) = C(22,2) (1/200)^2 (199/200)^20 = .005224..
*Sunday, March 9, 2014 at 12:45am*

**Statistics**

Prev Up Next (1 pt) Suppose that in the year 2000, the cost of a compact car averaged $ 12600 and that in 2003, the cost averaged $ 14100. Assuming that the relationship between year t and cost c is linear, develop a formula for predicting the average cost of a compact car in ...
*Saturday, March 8, 2014 at 5:14pm*

**Statistics**

Please only post your questions once. Repeating posts will not get a quicker response. In addition, it wastes our time looking over reposts that have already been answered in another post. Thank you.
*Saturday, March 8, 2014 at 12:58pm*

**Statistics**

Z = (score-mean)/SD Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability related to the Z score. OR… http://davidmlane.com/hyperstat/z_table.html
*Saturday, March 8, 2014 at 12:56pm*

**Statistics**

If the events are independent, the probability of both/all events occurring is determined by multiplying the probabilities of the individual events. 3/8 * 3/8 = ? 3/8 * (3-1)/(8-1) = ?
*Saturday, March 8, 2014 at 12:55pm*

**Statistics**

I have 8 marbles: 3 blue, 1 green, 4v reds. What is the probability of selecting a blue marble twice with replacement and twice without replacement
*Saturday, March 8, 2014 at 12:09pm*

**Statistics**

For the z-score mean-SD how do you get the percentage without using a calculator
*Saturday, March 8, 2014 at 11:22am*

**Statistics**

I thought I had given you the answer. finding the z-score results in a mean of 0 and a standard deviation of 1 so in the link I gave you .... http://davidmlane.com/hyperstat/z_table.html enter 0 for the mean 1 for the sd click on "below" and enter -.75 click ...
*Saturday, March 8, 2014 at 10:32am*

**Statistics**

If I don't know the mean and the standard deviation how can I find the area of z-score -0.75
*Saturday, March 8, 2014 at 10:28am*

**Statistics**

If I don't know the mean and the standard deviation how can I find the area of z-score -0.75
*Saturday, March 8, 2014 at 9:06am*

**Statistics**

Fun to play around with this excellent site http://davidmlane.com/hyperstat/z_table.html
*Saturday, March 8, 2014 at 8:41am*

**Statistics **

Consider the standard normal distribution. Find the area for the z-score -0.75. Draw a picture of this distribution showing the location of the z-score and the mean. Shade the region corresponding to the area found for the z-score.
*Saturday, March 8, 2014 at 8:37am*

**Statistics**

Use David's excellent "normal distribution" calculator http://davidmlane.com/hyperstat/z_table.html click on "area from a value" enter the data, click on "between" and enter 8 and 11 to get .4467 You can enter the data directly, no need...
*Saturday, March 8, 2014 at 7:53am*

**Statistics**

In a certain population of clover, the number of flowers on each plant is approximately normally distributed with a mean of 10.8 flowers/plant and a standard deviation of 2.1 flowers/plant. What percentage of the plants fall between 8 and 11 flowers?
*Saturday, March 8, 2014 at 7:09am*

**statistics**

In a random sample of 100 customers, 62 returned with a month. For a 95% confidence interval on the proportion of customers who return for an oil change, the lower limit is:
*Friday, March 7, 2014 at 11:21pm*

**Statistics**

393
*Friday, March 7, 2014 at 7:36pm*

**Statistics**

If the experiment involves two independent variables, the possibility of an interaction between the variables can be measured.
*Friday, March 7, 2014 at 4:07pm*

**Statistics**

Help please... What are some reason for conducting an experiment with two factors?
*Friday, March 7, 2014 at 3:16pm*

**statistics**

a large shipment of computer chips, of which 5% are actually defective, a quality control manager decides to test chips until he finds the first defective. What is the probability that the manager finds the first defective chip on the first test? in Homework Help
*Friday, March 7, 2014 at 4:04am*

**statistics**

.5
*Thursday, March 6, 2014 at 10:10pm*

**Statistics**

Pick any person. There are 16 people to shake hands with. Since there are 18 people, there are 18*16 shakes. But, counting this way, each shake is counted twice, once for each person. So, the final answer is 18*16/2
*Thursday, March 6, 2014 at 12:05pm*

**statistics**

ky
*Thursday, March 6, 2014 at 11:27am*

**Statistics**

If the king and queen invite 8 knights and thier wives then how many handshakes will there be if each couple cannot handshake with their lifetime partner. (I think this involves the king and queen as a couple).
*Thursday, March 6, 2014 at 9:55am*

**Statistics**

30
*Wednesday, March 5, 2014 at 9:09pm*

**statistics**

.05,.07
*Wednesday, March 5, 2014 at 5:23pm*

**statistics**

Please only post your questions once. Repeating posts will not get a quicker response. In addition, it wastes our time looking over reposts that have already been answered in another post. Thank you.
*Wednesday, March 5, 2014 at 2:25pm*

**statistics (?) **

What null hypothesis do you want to consider?
*Wednesday, March 5, 2014 at 2:24pm*

**statistics**

Post a null hypothesis that would use a t test statistical analysis.. Use the same hypothetical situation taken in the t test hypothesis, and turn it into a null hypothesis using a one-way ANOVA analysis and a two-way ANOVA.
*Wednesday, March 5, 2014 at 11:49am*

**statistics**

A telephone company's records indicate that private customers pay on average $17.10 per month for long-distance telephone calls. A random sample of 10 customers' bills during a given month produced a sample mean of $22.10 expended for long-distance calls and a sample ...
*Wednesday, March 5, 2014 at 11:45am*

**statistics**

Post a null hypothesis that would use a t test statistical analysis.. Use the same hypothetical situation taken in the t test hypothesis, and turn it into a null hypothesis using a one-way ANOVA analysis and a two-way ANOVA.
*Wednesday, March 5, 2014 at 11:22am*

**probability and statistics**

4
*Tuesday, March 4, 2014 at 10:14pm*

**statistics**

2
*Tuesday, March 4, 2014 at 9:06pm*

**math probability**

Z = (score-mean)/SD Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability related to the Z score.
*Tuesday, March 4, 2014 at 4:19pm*

**statistics**

Conduct an ANOVA comparing participants recall will vary as a function of stress levels. Conduct an ANOVA comparing participants recall at Time 1 across all three stress level conditions (low, medium,and high). Conduct post hoc tests if needed, using the Tukey method.
*Monday, March 3, 2014 at 8:12pm*

**statistics**

Poisson distribution (m = mean): P(x) = e^(-m) m^x / x! Values: x = 3 m = 5 Substitute and calculate.
*Monday, March 3, 2014 at 5:25pm*

**statistics**

Looks like you might be doing a one-way ANOVA test for the data you choose for this project. Your ANOVA summary table should have the following setup: Source.....SS.....df.....MS.....F Between Within Totals If you calculate by hand, here are a few hints: SS total = SS between...
*Monday, March 3, 2014 at 5:18pm*

**statistics**

Conduct an ANOVA comparing participants recall will vary as a function of stress levels. Conduct an ANOVA comparing participants recall at Time 1 across all three stress level conditions (low, medium, and high). Coduct post hoc tests if needed, using the Tukey method.Write a ...
*Monday, March 3, 2014 at 3:31pm*

**Statistics**

@John I have come from a year later to reply to your concern, to uproot this tyranny that is Math Guru. No longer shall we sit wondering what the other half of the question is. No longer must we be given a formula and have to solve it out. NO LONGER MUST WE SIT THROUGH THIS. ...
*Monday, March 3, 2014 at 2:53pm*

**Statistics**

I got only love for John. The answer is fate
*Monday, March 3, 2014 at 2:46pm*

**Statistics**

The answer is A, Math guru know what he be doin!
*Monday, March 3, 2014 at 2:36pm*

**statistics**

On the average five customers visit a children department store each hour. Using Poisson distribution, calculate the probability of three customers shop at the store.
*Monday, March 3, 2014 at 12:17pm*

**Statistics/Probability**

sw
*Sunday, March 2, 2014 at 3:47pm*

**statistics**

Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability related to the Z score. Percentile rank is the proportion below a particular score. OR… http://davidmlane.com/hyperstat/...
*Sunday, March 2, 2014 at 1:59pm*

**Statistics**

99% = mean ± 2.575 SEm SEm = SD/√n Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability related to the Z score. To include each end, double proportion.
*Sunday, March 2, 2014 at 1:54pm*

**Statistics (?)**

Data missing.
*Sunday, March 2, 2014 at 1:50pm*

**statistics**

the average score on the statistics quiz was a 70, and there was a standard deviation of 10 points. If the z-socre was -1.0 what is the percentile rank?
*Sunday, March 2, 2014 at 1:04pm*

**Statistics**

In a certain city of several million people, of the adults are unemployed. If a random sample of adults in this city is selected, approximate the probability that at least in the sample are unemployed. Use the normal approximation to the binomial with a correction for ...
*Saturday, March 1, 2014 at 8:56pm*

**Statistics**

An economist found that a random sample of 42 high school teachers had an average annual salary of $56,490. A previous study showed that the population standard deviation is $4150. Calculate the margin of error, E, for a 99% confidence interval for µ, the average annual ...
*Saturday, March 1, 2014 at 5:26pm*

**statistics**

Either-or probabilities are found by adding the individual probabilities. .43 + .14 = ?
*Saturday, March 1, 2014 at 12:57pm*

**statistics**

A survey among US adults of their favorite toppings on a cheese pizza reported that 43% favored pepperoni, 14% favored mushrooms, and 6% favored both pepperoni and mushrooms. What is the probability that a random adult favored pepperoni or mushrooms on their cheese pizza? ...
*Friday, February 28, 2014 at 8:56pm*

**Probability**

Statistics show that about 5% of all males are colorblind. Suppose that 20 males are selected at random. What is the probability that at least 4 of the 20 people are colorblind? My answer: I got 1-0.984 The answer key says 0.00257394
*Friday, February 28, 2014 at 7:49pm*

**Statistics**

0.0213
*Friday, February 28, 2014 at 7:47pm*

**statistics**

ewrw 6546
*Friday, February 28, 2014 at 6:00pm*

**statistics**

You are gaining information about the population. You are estimating the difference in population means by using the difference in the sample means. You also make a few assumptions, such as the populations have the same variance and the populations are normally distributed.
*Friday, February 28, 2014 at 5:42pm*

**statistics**

When calculating a confidence interval for the difference between two means, what information are you gaining? The means are from both same population and different? Thank you.
*Friday, February 28, 2014 at 4:47pm*

**Math (Statistics)**

Perfect data, one standard of devation below and above. so appr 68% or prob of .68 confirmed by David's webpage http://davidmlane.com/hyperstat/z_table.html fill in the data to see and get .6827
*Friday, February 28, 2014 at 3:54pm*

**Math (Statistics) **

The SAT scores of a certain population of students are approximately normally distributed with a mean and standard deviation of 1000 and 200 points, respectively. The probability that a student selected at random from the population has an SAT score between 800 and 1200 ...
*Friday, February 28, 2014 at 3:20pm*

**Statistics**

Are the means from the same population or different?
*Friday, February 28, 2014 at 2:32pm*

**Statistics**

If "the probability of birth is equal in all months," that means that you would expect 10 students to be born in each month. Would either distribution apply in this case?
*Friday, February 28, 2014 at 2:30pm*

**Statistics**

Assume it is known that the probability of birth is equal in all months. What is the probability that in the STAT class of 120 students, exactly 20 students have their birthdays in either August or September? Solve using (i) the exact Binomial distribution, (ii) the Normal ...
*Friday, February 28, 2014 at 9:56am*

**Statistics**

Never mind, figured it out :)
*Friday, February 28, 2014 at 9:28am*

**Statistics**

.68
*Friday, February 28, 2014 at 9:10am*

**Statistics**

Two of the biggest soft drink rivals, Pepsi and Coke, are very concerned about their market shares. The pie chart that follows claims that PepsiCo's share of the beverage market is 25%. Assume that this proportion will be close to the probability that a person selected at ...
*Friday, February 28, 2014 at 9:02am*

**Statistics**

When calculating a confidence interval for the difference between two means, what information are one gaining?
*Friday, February 28, 2014 at 8:49am*

**Statistics**

Nevermind! I figured out what I did wrong!
*Friday, February 28, 2014 at 12:24am*

**Statistics **

Let X be a binomial random variable with n = 100 and p = 0.2. Find approximations to these probabilities. (Round your answers to four decimal places.) P(17 < X < 28) I get the answer as 0.7059 but it is wrong. I can't seem to figure this out... Help please
*Thursday, February 27, 2014 at 11:57pm*

**engineering**

Building and construction A. Architecture B. Engineering C. Nursing D. Statistics
*Thursday, February 27, 2014 at 8:53pm*

**Statistics in Psychology**

a) Looks like a paired t-test (same subjects are used in a "before and after" scenario). b) Looks like an independent groups t-test (different subjects) c) Looks like a matched pairs t-test (matched based on characteristics like age).
*Thursday, February 27, 2014 at 5:27pm*

**Statistics**

Looks like an ANOVA design. If there were significant differences, then the test was statistically significant.
*Thursday, February 27, 2014 at 5:02pm*

**Statistics**

See previous post.
*Thursday, February 27, 2014 at 4:59pm*

**statistics**

0
*Thursday, February 27, 2014 at 4:04pm*

**statistics**

Aaa
*Thursday, February 27, 2014 at 3:39pm*

**statistics**

Z = (score-mean)/SD Either use the handout or find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability related to the Z score.
*Thursday, February 27, 2014 at 2:42pm*

**Statistics**

THE ANSWER IS 23! Don't listen to math guru. He lies
*Thursday, February 27, 2014 at 1:53pm*

**statistics**

6.416
*Wednesday, February 26, 2014 at 9:13pm*

**Statistics**

Don't have a TI-84 calculator, but.... Z = (score-mean)/SD Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability (.80) related to a Z score. Insert that value into the above ...
*Wednesday, February 26, 2014 at 12:32pm*

**behavioral statistics**

Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportions/probabilities to compare their Z scores (the most common type of standard score).
*Wednesday, February 26, 2014 at 12:23pm*

**statistics**

You have a score on a national entrance exam of 95. What percentage of people in the population have a score that is lower than yours? (Assume the population mean is 75 and the standard deviation is 10. Use the table I passed out in class.)
*Wednesday, February 26, 2014 at 11:47am*

**Statistics**

A report says that the between-subjects factor of participants’ salary produced significant differences in self-esteem. (a) What does this tell you about the design? (b) What does it tell you about the results?
*Wednesday, February 26, 2014 at 10:43am*

**Statistics**

A report says that the between-subjects factor of participants’ salary produced significant differences in self-esteem. (a) What does this tell you about the design? (b) What does it tell you about the results? 19.(a) Source Sum Squares df Mean Square F Between 134.800 3 ...
*Wednesday, February 26, 2014 at 10:41am*

**Statistics in Psychology**

Please Help! For the following, which type of t-test is required? (a) Studying the effects of a memory drug on Alzheimer’s patients, testing a group of patients before and after administration of the drug. (b) Studying whether men and women rate the persuasiveness of an ...
*Wednesday, February 26, 2014 at 9:11am*

**Statistics**

Thank you! :)
*Wednesday, February 26, 2014 at 7:56am*

**behavioral statistics**

How could you use standard scores and the standard distribution to compare the reading scores of two students receiving special reading resource help and one student in a standard classroom who does not get special help?
*Tuesday, February 25, 2014 at 8:29pm*

**statistics**

I'll get you started. CI90 = p ± (1.645)[√(pq/n)] ...where p = x/n, q = 1 - p, and n = sample size. Note: ± 1.645 represents 90% confidence interval. For p in your problem: 26/40 For q in your problem: 14/40 n = 40 I let you take it from here to ...
*Tuesday, February 25, 2014 at 7:30pm*

**statistics**

Use a confidence interval formula for proportions. Here's one example: CI99 = p + or - (2.58)(sqrt of pq/n) ...where sqrt = square root, p = x/n, q = 1 - p, and n = sample size. p = 120/400 q = 280/400 n = 400 Convert all fractions to decimals before using the formula to ...
*Tuesday, February 25, 2014 at 7:17pm*

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