A statistics professor takes a random sample of 25 students who have taken a special statistics class.  He wants to test the null hypothesis that the grades of these students are, on average, less than or equal to those of the population of students who take the regular statistics test.  The mean grade for the population is 75.  The mean grade for the sample is 86 with a standard deviation of 10.  Using a significance level of .05, test the null hypothesis.

A Statistics instructor wanted to compare the scores on the same final exam given to students at a local community college and local university.  The Statistics instructor feels that students at the community college would be better prepared and have higher exam scores on the final exam. After grading the final exams from both institutions, the Statistics instructor found that for a sample of 36 community college students, the sample had a mean score of 84 with a standard deviation of 3.4.  A sample of 45 university students had a mean score 79 with a standard deviation of 2.6.  Construct a 95% confidence interval for the difference between population mean exam scores. Round your final results to one decimal place.      _____________     ≤      ???  −  ?????      ≤     ______________

A professor believes that, for the introductory art history classes at his university, the mean test score of students in the evening classes is lower than the mean test score of students in the morning classes. He collects data from a random sample of 250 students in evening classes and finds that they have a mean test score of 88.1. He knows the population standard deviation for the evening classes to be 4.2 points. A random sample of 150 students from morning classes results in a mean test score of 89.1. He knows the population standard deviation for the morning classes to be 7.7 points. Test his claim with a 95 % level of confidence. Let students in the evening classes be Population 1 and let students in the morning classes be Population 2. Step 2 of 3: Compute the value of the test statistic. Round your answer to two decimal places.

Entry to a certain University is determined by a national test. The scores on this test are normally distributed with a mean of 500 and a standard deviation of 100. Tom wants to be admitted to this university and he knows that he must score better than at least 80% of the students who took the test. Tom takes the test and scores 595. Will he be admitted to this university?

A professor believes that, for the introductory art history classes at his university, the mean test score of students in the evening classes is lower than the mean test score of students in the morning classes. He collects data from a random sample of 250 students in evening classes and finds that they have a mean test score of 76.8. He knows the population standard deviation for the evening classes to be 7.2 points. A random sample of 200 students from morning classes results in a mean test score of 77.8. He knows the population standard deviation for the morning classes to be 1.9 points. Test his claim with a 90% level of confidence. Let students in the evening classes be Population 1 and let students in the morning classes be Population 2. Step 1 of 3 :  State the null and alternative hypotheses for the test. Fill in the blank below. H0: μ1=μ2 Ha: μ1__μ2

You may need to use the appropriate technology to answer this question. Data were collected on the top 1,000 financial advisers. Company A had 239 people on the list and another company, Company B, had 121 people on the list. A sample of 16 of the advisers from Company A and 10 of the advisers from Company B showed that the advisers managed many very large accounts with a large variance in the total amount of funds managed. The standard deviation of the amount managed by advisers from Company A was s₁ = $583 million. The standard deviation of the amount managed by advisers from Company B was s₂ = $484 million. Conduct a hypothesis test at a = 0.10 to determine if there is a significant difference in the population variances for the amounts managed by the two companies. What is your conclusion about the variability in the amount of funds managed by advisers from the two firms? State the null and alternative hypotheses. 2 2 H₂:0 2 Find the value of the test statistic. (Round your answer…

The manager of a major retail store has taken a random sample of 25 customers. The average sale was $52.50. The population standard deviation is known to be $6.10. The manager would like to determine whether or not the mean sales by all customers are significantly more than $50. What is the p-value for the test?

Fran is training for her first marathon, and she wants to know if there is a significant difference between the mean number of miles run each week by group runners and individual runners who are training for marathons. She interviews 42 randomly selected people who train in groups and finds that they run a mean of 47.1 miles per week. Assume that the population standard deviation for group runners is known to be 4.4 miles per week. She also interviews a random sample of 47 people who train on their own and finds that they run a mean of 48.5 miles per week. Assume that the population standard deviation for people who run by themselves is 1.8 miles per week. Test the claim at the 0.01 level of significance. Let group runners training for marathons be Population 1 and let individual runners training for marathons be Population 2.   Step 2 of 3 :   Compute the value of the test statistic. Round your answer to two decimal places.

Airline companies are interested in the consistency of the number of babies on each flight, so that they have adequate safety equipment. They are also interested in the variation of the number of Babies. Suppose that an airline executive believes the standard deviation in the number of babies is 6 at the most. The airline conducts a survey. The results of the 23 flights surveyed give a samle mean of 8 with a sample standard deviation of 9. Test the executive's belief to see if it is accurate, or if it is actually greater at the a = 0.05 level. Ho:o = H:o Select an answer df = P-value = The p-value is... greater than a less than (or equal to) a This test statistic leads to a decision to... reject the null fail to reject the null accept the alternative accept the null As such, the final conclusion is that there Select an answer v sufficient evidence to conclude the standard deviation of the number of babies on airplanes is Select an answer than (?

A newspaper article reports that the mean cost for preventative dental care per year is $175 with a standard deviation of $35 (assume that this is the population standard deviation). You want to test whether the mean cost for preventative dental care in your company is different from what was reported in the article. You take a random sample of 250 employees and find the mean cost is $171. Does this signficantly differ from what was reported in the article? Run the appropriate test at α=0.05. Give each of the following to receive full credit: 1) the appropriate null and alternative hypotheses; 2) the appropriate test; 3) the decision rule; 4) the calculation of the test statistic; and 5) your conclusion including a comparison to alpha or the critical value. You MUST show your work to receive full credit. Partial credit is available.