Sunday

April 19, 2015

April 19, 2015

**Recent Homework Questions About Statistics**

**statistics**

A researcher was interested in assessing the effectiveness of the Statistics Diet as compared to a regular low calorie diet on weight loss. In the study, obese participants were randomly assigned to one of two groups: (1) the Statistics Diet, which required participants to ...
*Sunday, May 4, 2014 at 3:43pm*

**Statistics**

Reginald Brown an inspector from the department of weights and measures, weighs 15 eighteen-ounce cereal boxes of corn flakes. he finds their mean weight to be 17.78 ounces with a standard deviation of .4 ounces. are the cereal boxes lighter than they should be? let Alpha = .01
*Sunday, May 4, 2014 at 3:06pm*

**statistics**

John Davis, a manager of a supermarket, wants to estimate the proportion of customers that will be using food stamps at his store. How large a sample is required to estimate the true proportion to within 3% with 98% confidence?
*Sunday, May 4, 2014 at 2:26pm*

**Statistics**

σ = sqrt[ P * ( 1 - P ) / n ] = sqrt [(0.8 * 0.2) / 100] = sqrt(0.0016) = 0.04 z = (p - P) / σ = (.73 - .80)/0.04 = -1.75. What type of formula is this problem?
*Sunday, May 4, 2014 at 12:47pm*

**statistics**

a medication is 75% effective against a bacterial infection. find the probability that if 12 people take the medication, at least 1 person"s infection will not improve
*Sunday, May 4, 2014 at 10:03am*

**Statistics**

I am a big shot research scientist at Washington University where I am using 2ebrafish to study neuronal migration. My graduate students measured 40 fish and found that the mean length of the fish sampled was 3.7 cm with a standard deviation of 0.5 cm. Construct a 95% ...
*Sunday, May 4, 2014 at 8:49am*

**Statistics **

If I'm sampling 50 people and 35 people liked Pepsi instead of Coke how can i apply that to the test statistics for a mean t=x(bar)-mule/s/ square root n
*Sunday, May 4, 2014 at 4:05am*

**applied statistics**

how to remember the difference between dependent and independent variable and which one is X n Y ?
*Sunday, May 4, 2014 at 2:31am*

**statistics**

A researcher was interested in assessing the effectiveness of the Statistics Diet as compared to a regular low calorie diet on weight loss. In the study, obese participants were randomly assigned to one of two groups: (1) the Statistics Diet, which required participants to ...
*Saturday, May 3, 2014 at 9:45pm*

**Statistics**

Im using this equation to complete this question: So for this question, I want to determine how many people like Pepsi and how many people like Coca-Cola. Then I want to determine how many people like X over Y. For example, if 35 out of 50 people prefer Pepsi over Coca-Cola. ...
*Saturday, May 3, 2014 at 8:44pm*

**statistics**

It has been suggested that the rate of forgetting (coded as normal vs. fast) for word lists often used in psychological experiments may depend on the type of memory test employed, either free-recall or recognition. What is the best way to test this hypothesis? a. regression b...
*Saturday, May 3, 2014 at 6:00pm*

**statistics**

17. A newspaper article reported that the typical American family spent an average of $75 for Easter candy last year. A sample of N=16 families this year reported spending a mean of $85, with a standard deviation of $20. What hypothesis testing technique should be used to ...
*Saturday, May 3, 2014 at 5:30pm*

**statistics**

A researcher was interested in assessing the effectiveness of the Statistics Diet as compared to a regular low calorie diet on weight loss. In the study, obese participants were randomly assigned to one of two groups: (1) the Statistics Diet, which required participants to ...
*Saturday, May 3, 2014 at 1:56pm*

**statistics**

It has been suggested that the rate of forgetting (coded as normal vs. fast) for word lists often used in psychological experiments may depend on the type of memory test employed, either free-recall or recognition. What is the best way to test this hypothesis? a. regression b...
*Saturday, May 3, 2014 at 12:48pm*

**statistics**

A researcher was interested in assessing the effectiveness of the Statistics Diet as compared to a regular low calorie diet on weight loss. In the study, obese participants were randomly assigned to one of two groups: (1) the Statistics Diet, which required participants to ...
*Saturday, May 3, 2014 at 12:41pm*

**statistics**

A researcher was interested in assessing the effectiveness of the Statistics Diet as compared to a regular low calorie diet on weight loss. In the study, obese participants were randomly assigned to one of two groups: (1) the Statistics Diet, which required participants to ...
*Friday, May 2, 2014 at 7:09pm*

**statistics**

A researcher was interested in assessing the effectiveness of the Statistics Diet as compared to a regular low calorie diet on weight loss. In the study, obese participants were randomly assigned to one of two groups: (1) the Statistics Diet, which required participants to ...
*Friday, May 2, 2014 at 6:21pm*

**statistics**

Table: Like Dogs Yes No Like cats Yes 194 21 No 110 10 For parts a-d give a fraction and % for answer. A.What % of all students like dogs? B. What % of students in the entire class like dogs and cats? C. What % of students who like cats like dogs? D. What % of students who do ...
*Friday, May 2, 2014 at 12:17pm*

**Statistics**

As the sample size gets larger, what happens to the size of the correlation that is needed for significance?
*Friday, May 2, 2014 at 10:29am*

**Statistics - Help!!!**

An independent measures research study compares three treatment conditions using a sample of n=5 in each treatment. For this study, the three samples have SS1=10, SS2=20, SS3= 15. What value would be obtained for MS within?
*Friday, May 2, 2014 at 10:29am*

**statistics**

A research study comparing three treatments with n=5 in each treatment produces T1=5, T2=10, T3=15 with SS1=6, SS2=9, SS3=9 and (Greek letter E)X squared =94. What is SS total? What is SS between and what is SS within?
*Friday, May 2, 2014 at 10:05am*

**statistics**

At the beginning of the semester, students who registered for a statistics course were randomly assigned to two sections, each taught by a different instructor. At the end of the semester, we would like to test whether there are differences in performance on the final exam ...
*Thursday, May 1, 2014 at 9:02pm*

**Statistics **

You want to know if there's a difference between the proportions of high school students and college students who read newspapers regularly. out of a random sample of 500 high-school students, 287 say they read newspapers regularly, and out of a random sample of 420 ...
*Thursday, May 1, 2014 at 11:45am*

**Statistics **

You want to know if there's a difference between the proportions of high school students and college students who read newspapers regularly. out of a random sample of 500 high-school students, 287 say they read newspapers regularly, and out of a random sample of 420 ...
*Thursday, May 1, 2014 at 11:37am*

**Statistics**

Carol has data on the causes of violent outbursts among kindergarten children. She used a "shot-gun" approach to hypothesis testing by asking the computer to produce p-values for 300 quickly chosen hypothesis tests. She shared her glee with fellow researchers, noting...
*Thursday, May 1, 2014 at 8:27am*

**Statistics**

A 95% confidence level for the difference between u1 and u2 runs from -2 to +6. From this we can infer that a. u1 is probably greater than u2. b. u1 is probably less than u2. c. there may be no difference at all between u1 and u2. d. the difference between u1 and u2 is not ...
*Thursday, May 1, 2014 at 8:26am*

**Probability**

We are given the following statistics about the number of children in the families of a small village. There are 100 families: 10 families have no children, 40 families have 1 child each, 30 families have 2 children each, 10 families have 3 each, and 10 families have 4 each. ...
*Thursday, May 1, 2014 at 4:03am*

**statistics**

Chicken Delight claims that 86 percent of its orders are delivered within 10 minutes of the time the order is placed. A sample of 70 orders revealed that 57 were delivered within the promised time. At the .02 significance level, can we conclude that less than 86 percent of the...
*Wednesday, April 30, 2014 at 9:22pm*

**statistics**

A researcher was interested in assessing the effectiveness of the Statistics Diet as compared to a regular low calorie diet on weight loss. In the study, obese participants were randomly assigned to one of two groups: (1) the Statistics Diet, which required participants to ...
*Wednesday, April 30, 2014 at 9:20pm*

**Statistics 220**

suppose 59 cars start at a car race, how many ways can the top car finish the race?
*Wednesday, April 30, 2014 at 7:43pm*

**Statistics**

A 95% confidence level for the difference between u1 and u2 runs from -2 to +6. From this we can infer that a. u1 is probably greater than u2. b. u1 is probably less than u2. c. there may be no difference at all between u1 and u2. d. the difference between u1 and u2 is not ...
*Wednesday, April 30, 2014 at 7:28pm*

**Statistics**

It is said that healthy and happy workers are efficient and productive. A company that manufactures exercising machines wanted to know the percentage of large companies that provided on-site health club facilities. A sample of 240 companies showed that 96 of them provide such ...
*Wednesday, April 30, 2014 at 7:27pm*

**Statistics**

Carol has data on the causes of violent outbursts among kindergarten children. She used a "shot-gun" approach to hypothesis testing by asking the computer to produce p-values for 300 quickly chosen hypothesis tests. She shared her glee with fellow researchers, noting...
*Wednesday, April 30, 2014 at 7:25pm*

**statistics**

what is the variance and standard deviation of the following numbers:14,16,26,36,12,16
*Wednesday, April 30, 2014 at 3:52pm*

**statistics**

For hair color, Brown (B) is a dominant trait and Blond (b) is a recessive trait. If one parent has pure blond hair and one parent has hybrid brown hair, complete the Punnett square and questions that follow. a) What is the probability that their first child will have pure ...
*Wednesday, April 30, 2014 at 3:51pm*

**statistics**

here are 12 qualified applicants for 8 trainee positions in a fast-food management program. How many different groups of trainees can be selected?
*Wednesday, April 30, 2014 at 2:47pm*

**statistics**

The mean income per person in the United States is 36,500
*Wednesday, April 30, 2014 at 1:51pm*

**Statistics**

Tukey's HSD test is used a. prior to performing a one-way ANOVA. b. to determine the amount of difference between group means. c. to determine whether the overall difference among groups means is significant. d. to locate "true" differences after a significant F
*Wednesday, April 30, 2014 at 12:34pm*

**Statistics**

Given: The difference between two dependent means is statistically significant. The reason behind this outcome can be difficult to determine when a. population standard deviations are estimated from samples. b. sample size is large. c. a large value of t is obtained. d. ...
*Wednesday, April 30, 2014 at 12:32pm*

**statistics**

A fictional study was used to examine the effect of a new antianxiety drug on levels of anxiety. Sixty participants were randomly assigned to one of two groups: 1) new antianxiety pill and 2) placebo pill. One hour after taking the medication or placebo, all of the ...
*Wednesday, April 30, 2014 at 10:58am*

**statistics**

construct a 95% confidence interval for the difference betwen the proportions of high-school students an college students who read newspapers regularly.
*Wednesday, April 30, 2014 at 12:03am*

**statistics**

Build a 95% confidence interval for the mean of the population from the given sample data. Assume that the population has a normal distribution. 16.4, 15.7, 16.2, 15.8 17.1 15.8, 15.9, 16.0, 16.4 15.0 *please help me solve this! I have no clue what I am supposed to do
*Tuesday, April 29, 2014 at 10:13pm*

**Statistics**

Tukey's HSD test is used a. prior to performing a one-way ANOVA. b. to determine the amount of difference between group means. c. to determine whether the overall difference among groups means is significant. d. to locate "true" differences after a significant F
*Tuesday, April 29, 2014 at 10:13pm*

**Statistics**

Given: The difference between two dependent means is statistically significant. The reason behind this outcome can be difficult to determine when a. population standard deviations are estimated from samples. b. sample size is large. c. a large value of t is obtained. d. ...
*Tuesday, April 29, 2014 at 9:47pm*

**statistics**

It is known that the population mean for the Quantitative section of the GRE is 500, with a standard deviation of 100. In 2006, a sample of 400 students taking the GRE, whose family income was between $70,000 and $80,000, had a quantitative GRE score of 511. Perform a one-...
*Tuesday, April 29, 2014 at 9:21pm*

**statistics**

A professor is interested in the relationship between the number of hours students study for a quiz and their quiz grades. She asked each student to record the number of hours that he/she studied for the final exam. She also recorded the students’ grades in percentages (...
*Tuesday, April 29, 2014 at 9:19pm*

**statistics**

1000 raffle tickets are sold and the winner is chosen at random there is only one prize $500 in cash you buy one ticket(a) what is the probability you will win the prize of $500 (b) your expected earnings can be found by multiplying the value of the prize by the probability ...
*Tuesday, April 29, 2014 at 8:28pm*

**Probability**

We are given the following statistics about the number of children in the families of a small village. There are 100 families: 10 families have no children, 40 families have 1 child each, 30 families have 2 children each, 10 families have 3 each, and 10 families have 4 each. ...
*Tuesday, April 29, 2014 at 7:34pm*

**probability**

PROBLEM 7: SAMPLING FAMILIES (3 points possible) We are given the following statistics about the number of children in the families of a small village. There are 100 families: 10 families have no children, 40 families have 1 child each, 30 families have 2 children each, 10 ...
*Tuesday, April 29, 2014 at 5:54pm*

**Statistics**

In order to critical values of t to be precisely correct for testing Ho: u1-u2=0 using small independent samples, we must assume a. ó1 = ó2 b. normality of populations c. u1 = u2 d. all of the above.
*Tuesday, April 29, 2014 at 1:00pm*

**Statistics**

In one-way ANOVA involving three groups, the alternative hypothesis would be considered correct if, in the population, a. all means were equal. b. two means are equal but the third is different. c. all three means have different values. d. either (b) or (c) above is true.
*Tuesday, April 29, 2014 at 12:54pm*

**Statistics**

Professor Casey performs a t test of Ho: u1 - u2=0 using a-.01 and finds a significant difference between Xmean1 and Xmean2. From this we can infer. a. a large difference between u1 and u2. b. an important difference betwee u1 and u2. c. u1 and u2 to be unequal. d. all of the ...
*Tuesday, April 29, 2014 at 12:51pm*

**ap statistics**

Seventy-five (75) people with hypertension were given a new drug for the treatment of their condition. Blood pressure was lowered sufficiently to reduce the risk of serious outcomes in 20 of the 75 patients.
(B) Calculate a 95% confidence interval for the proportion. ...
*Tuesday, April 29, 2014 at 10:41am*

**statistics**

A researcher is testing the effect of a new cold and flu medication on mental alertness. A sample of n=9 college students is obtained and each student is given the normal dose of the medicine. Thirty minutes later, each students performance is measured on a video game that ...
*Tuesday, April 29, 2014 at 12:19am*

**Statistics **

If the critical z value for a hypothesis test equals 2.45, what value of the test statistic would provide the least chance of making a Type I error? 3.74 10,000 2.46 4.56
*Monday, April 28, 2014 at 11:06pm*

**statistics**

for a hypothesis comparing two population means, what is the critical value for a one-tailed hypothesis test, using a 5percent level of significance level, with both sample sizes equal to 13? the standard deviations for the samples are 5 and 7. assume the population standard ...
*Monday, April 28, 2014 at 9:30pm*

**statistics**

if we are testing for the difference between two populations, it is assumed that the two populations are approximately normal and have equal variances, true or false
*Monday, April 28, 2014 at 9:28pm*

**statistics**

A clinical psychologist notices that admission to the psychiatric hospital she works at seem to vary by season. Using a chi-square test, she rejects the null hypothesis that hospital admission is independent of season. What conclusions can she make? a. Hospital admissions are ...
*Monday, April 28, 2014 at 9:15pm*

**Statistics**

A song must be n longer than 3 minutes and 30 seconds, or (210 seconds) Micheal Jackson founds out that his mean song length is 244.6 seconds with a standard deviation of 29/3 seconds. What is the null hypothesis and the alternative hypothesis, what is the right formula and ...
*Monday, April 28, 2014 at 2:33pm*

**Statistics**

A song must be n longer than 3 minutes and 30 seconds, or (210 seconds) Micheal Jackson founds out that his mean song length is 244.6 seconds with a standard deviation of 29/3 seconds. What is the null hypothesis and the alternative hypothesis, what is the right formula and ...
*Monday, April 28, 2014 at 12:34am*

**Statistics**

Construct a 95% confidence interval for population mean: My friends measured 40 fish and found that the mean length of the fish sampled was 3.7 cm with a standard deviation of 0.5 cm.
*Monday, April 28, 2014 at 12:06am*

**Economics and statistics **

If the critical z value for a hypothesis test equals 2.45, what value of the test statistic would provide the least chance of making a Type I error? 3.74 10,000 2.46 4.56
*Sunday, April 27, 2014 at 11:52pm*

**Statistics**

What percentage of cats sleep less than 10 hours? What percentage sleep more than 20 hours
*Sunday, April 27, 2014 at 11:33pm*

**Statistics**

the average numbers of hours a cat sleep is approximately normally distributed with a mean of 15 hours and a standard deviation of 1.7 hours; what percentage of cats sleep between 13 and 18 hours
*Sunday, April 27, 2014 at 10:54pm*

**Statistics**

The claim that "38% of those persons who retired from an industrial job before the age of 60 would return to work if a suitable job was available," is to be investigated at the 0.02 level of risk. If 86 out of the 200 workers sampled said they would return to work, ...
*Sunday, April 27, 2014 at 6:16pm*

**Statistics**

A simple random sample of 27 adult mice has a length standard deviation of 0.66 mm. Using a 0.10 level of significance, does it appear that these mice come from a population with a length standard deviation of 0.87 mm?
*Sunday, April 27, 2014 at 5:57pm*

**Statistics**

A simple random sample of 27 adult mice has a length standard deviation of 0.66 mm. Using a 0.10 level of significance, does it appear that these mice come from a population with a length standard deviation of 0.87 mm?
*Sunday, April 27, 2014 at 4:46pm*

**Statistics**

One survey by the American Medical Association showed that among 785 randomly selected people who completed four years of college, 81.7% do not smoke. Use a 0.01 significance level to test the claim that people who completed four years of college are more likely to not smoke ...
*Sunday, April 27, 2014 at 4:46pm*

**statistics**

For which of the following would it be most appropriate to use an ANOVA to analyze the data? A. A researcher is interested in determining the most effective format for advertising. He randomly assigns 60 people to one of three groups: (1) television commercial, (2) radio ...
*Sunday, April 27, 2014 at 4:42pm*

**Statistics**

Health issues due to being overweight affect all age groups. of children and adolescents 6-11 years of age,18.8% are found to be overweight. A school district randomly sampled 130 in this age group and found that 20 were considered overweight. at Alpha =.05 is this less than ...
*Sunday, April 27, 2014 at 3:55pm*

**Statistics**

Two groups of climbers (team A and Team B) attempt to climb Mount everest using different routes. The probability of Team A reaching the summit is .70, The probability of Team B reaching the summit is .85. A. Sue calculated the probability the both teams reach the top in the ...
*Sunday, April 27, 2014 at 1:13pm*

**Statistics **

One survey by the American Medical Association showed that among 785 randomly selected people who completed four years of college, 81.7% do not smoke. Use a 0.01 significance level to test the claim that people who completed four years of college are more likely to not smoke ...
*Sunday, April 27, 2014 at 12:32pm*

**statistics**

If 30% of people in an area are registered voters and 15 people are selected at random from the area: A. what is the probability that at most 3 out of the 15 people are registered voters? B. could we have used the normal approximation to the binomial in part b? Explain why or ...
*Sunday, April 27, 2014 at 11:11am*

**Statistics**

A simple random sample of 27 adult mice has a length standard deviation of 0.66 mm. Using a 0.10 level of significance, does it appear that these mice come from a population with a length standard deviation of 0.87 mm?
*Sunday, April 27, 2014 at 10:35am*

**statistics**

A basketball scout randomly selected 144 players and timed how long each player took to perform a certain drill. The times in this sample were distributed with a mean of 8 minutes. The population standard deviation was known to be 3 minutes. A. find the critical value for a 95...
*Sunday, April 27, 2014 at 10:32am*

**statistics**

A random sample of 49 credit ratings is obtained, and it is found that they have a (sample) mean of 679.3 and a sample standard deviation of 95.9. Using a 0.05 level of significance, test the claim that these credit ratings are from a population with a mean that is equal to 700.
*Sunday, April 27, 2014 at 10:32am*

**statistics (7)**

The average cost per night of a hotel room in New York City is $273 (SmartMoney, March 2009). Assume this estimate is based on a sample of 45 hotels and that the sample standard deviation is $65. a. With 95% confidence, what is the margin of error (to 2 decimals)? b. What is ...
*Saturday, April 26, 2014 at 10:45pm*

**statistics**

The state bridge design engineer has devised a plan to repair North Carolina's 4420 bridges that are currently listed as being in either poor or fair condition. The state has a total of 13,168 bridges. Before the governor will include the cost of this plan in his budget, ...
*Saturday, April 26, 2014 at 3:10pm*

**ap statistics**

What would the null and alternate hypothesis be? A fire insurance company felt that the mean distance from a home to the nearest fire department in a suburb of Chicago was at least 4.7 miles. It set its fire insurance rates accordingly. Members of the community set out to show...
*Saturday, April 26, 2014 at 2:12pm*

**ap statistics**

What would the null and alternate hypothesis be for this problem? The manager at Air Cargo feels that the weights of packages shipped recently are less than in the past. Records show that in the past packages have had a mean weight of 36.7 lb. and a variance of 201.64 lb2. A ...
*Saturday, April 26, 2014 at 2:11pm*

**statistics**

Some students were asked, "Would you date someone with a great personality even though you did not find that person to be attractive?" Of the 131 women surveyed, 61.1% said yes, and of the 61 men surveyed, 42.6% said yes. Is there sufficient evidence to conclude that...
*Saturday, April 26, 2014 at 11:37am*

**statistics**

A researcher believe that college students spend a different amount of time talking on the phone than they do instant messaging. She takes a random sample of 12 college students and records the number of hours per week each student spends on each activity and plans to test at ...
*Saturday, April 26, 2014 at 11:34am*

**ap statistics**

A fire insurance company felt that the mean distance from a home to the nearest fire department in a suburb of Chicago was at least 4.7 miles. It set its fire insurance rates accordingly. Members of the community set out to show that the mean distance was less than 4.7 miles. ...
*Friday, April 25, 2014 at 9:35pm*

**ap statistics**

The manager at Air Cargo feels that the weights of packages shipped recently are less than in the past. Records show that in the past packages have had a mean weight of 36.7 lb. and a variance of 201.64 lb2. A random sample of last months shipping yielded a mean weight of 32.1...
*Friday, April 25, 2014 at 9:33pm*

**statistics**

Which of the following statements is correct? A. An extremely small p-value indicates that the actual data differs markedly from that expected if the null hypothesis were true. B. A large p-value indicates that the data is consistent with the alternative hypothesis. C. The p-...
*Friday, April 25, 2014 at 10:29am*

**ap statistics**

What is the mean of the sample means? What is the standard deviation of the sample means?
*Friday, April 25, 2014 at 9:43am*

**Statistics **

For the following set of scores: X Y 6 4 3 1 5 0 6 7 4 2 6 4 a) Compute the Pearson correlation. b) Add 2 points to each X value and compute the correlation for the modified scores. How does adding a constant to every score affect the value of the correlation? c)Multiply each ...
*Thursday, April 24, 2014 at 10:54pm*

**statistics**

In which of the following situations would it not be appropriate to use a paired t-test to analyze the data? A. A marriage therapist believes that many couples have different perspectives regarding the state of their marriages, prior to the start of couples therapy. In order ...
*Thursday, April 24, 2014 at 9:14pm*

**Statistics**

From the following list of number of discharges each day in September, compute the mean, median, mode, and range. Round the mean and median to one decimal point. Day # of discharges 1 27 2 22 3 35 4 63 5 42 6 55 7 62 8 65 9 32 10 35 11 36 12 75 13 65 14 84 15 37 16 38 17 62 18...
*Thursday, April 24, 2014 at 5:25pm*

**ap statistics**

Which of the following is not correct? A. The rejection region is controlled by the alpha level and the alternate hypothesis. B. The p-value measures the probability that the null hypothesis is true. C. The probability of a Type I error is controlled by the selection of the ...
*Thursday, April 24, 2014 at 3:55pm*

**ap statistics**

In hypothesis testing, β is the probability of committing an error of Type II. The power of the test, 1 - β, is then: A. the probability of failing to reject H0. B. the probability of rejecting H0 when HA is true C. the probability of failing to reject H0 when H0 is ...
*Thursday, April 24, 2014 at 3:51pm*

**ap statistics**

An unnoticed mechanical failure has caused one-fourth of a machine shop’s production of 10000 pistol firing pins to be defective. A random sample of 25 firing pins was drawn from the population. a.) Explain why this random variable has a binomial distribution? (2 points) ...
*Thursday, April 24, 2014 at 3:20pm*

**ap statistics**

An unnoticed mechanical failure has caused one-fourth of a machine shop’s production of 10000 pistol firing pins to be defective. A random sample of 25 firing pins was drawn from the population. a.) Explain why this random variable has a binomial distribution? (2 points) ...
*Thursday, April 24, 2014 at 3:08pm*

**ap statistics**

What is the mean of the sample means? What is the standard deviation of the sample means?
*Thursday, April 24, 2014 at 3:08pm*

**ap statistics**

In a survey, 600 mothers and fathers were asked about the importance of sports for boys and girls. Of the parents interviewed, 70% said the genders are equal and should have equal opportunities to participate in sports. B. Using the normal approximation without the continuity ...
*Thursday, April 24, 2014 at 2:54pm*

**ap statistics**

An unnoticed mechanical failure has caused one-fourth of a machine shop’s production of 10000 pistol firing pins to be defective. A random sample of 25 firing pins was drawn from the population. a.) Explain why this random variable has a binomial distribution? (2 points) ...
*Thursday, April 24, 2014 at 2:34pm*

**Statistics**

Prof. C is studying a population of the elementary school pupils in a school district with data on all its children. Another prof. suggests he calculate a confidence interval to estimate the mean age of the children. Prof C responds that it is not necessary. Explain why Prof. ...
*Wednesday, April 23, 2014 at 11:51pm*

**statistics (7)**

The average cost per night of a hotel room in New York City is $273 (SmartMoney, March 2009). Assume this estimate is based on a sample of 45 hotels and that the sample standard deviation is $65. a. With 95% confidence, what is the margin of error (to 2 decimals)? b. What is ...
*Wednesday, April 23, 2014 at 9:11pm*

**statistics (6)**

The International Air Transport Association surveys business travelers to develop quality ratings for transatlantic gateway airports. The maximum possible rating is 10. Suppose a simple random sample of 50 business travelers is selected and each traveler is asked to provide a ...
*Wednesday, April 23, 2014 at 8:44pm*

**statistics (4)**

For a t distribution with 16 degrees of freedom, find the area, or probability, in each region. a. To the right of 2.120. (Use 3 decimals.)
*Wednesday, April 23, 2014 at 8:44pm*