A new small business wants to know if its current radio advertising is effective. The owners decide to look at the mean number of customers who make a purchase in the store on days immediately following days when the radio ads are played as compared to the mean for those days following days when no radio advertisements are played. They found that for 7 days following no advertisements, the mean was 22.1 purchasing customers with a standard deviation of 1.2 customers. On 10 days following advertising, the mean was 24.1 purchasing customers with a standard deviation of 1.6 customers. Test the claim, at the 0.05 level, that the mean number of customers who make a purchase in the store is lower for days following no advertising compared to days following advertising. Assume that both populations are approximately normal and that the population variances are equal. Let days following no advertisements be Population 1 and let days following advertising be Population 2. Step 1 of 3: State the null and alternative hypotheses for the test. Fill in the blank below. Ho:μ₁ = ₂ Ha: M₁ •μ₂

It seems these days that college graduates who are employed full-time work more than 40-hour weeks. Data are available that can help us decide if this is true. A survey was recently sent to a group of adults selected at random. There were 15 respondents who were college graduates employed full-time. The mean number of hours worked per week by these 15 respondents was 43 hours, with a standard deviation of 8 hours. Assume that the population of hours worked per week by college graduates employed full-time is normally distributed with mean μ. Can we conclude that μ is greater than 40 hours? Use the 0.05 level of significance. State the null hypothesis  H0  and the alternative hypothesis  H1 Find the t-test df & Solve the t-test value  Find the critical value Can we conclude, at the 0.05 level of significance, that the mean number of hours worked per week by college graduates is greater than 40 hours? Yes or No?

One year Perry had the lowest ERA (earned-run average, mean number of runs yielded per nine innings pitched) of any male pitcher at his school, with an ERA of 2.81. Also, Jane had the lowest ERA of any female pitcher at the school with an ERA of 3.34. For the males, the mean ERA was 4.953 and the standard deviation was 0.724. For the females, the mean ERA was 5.079 and the standard deviation was 0.804. Find their respective z-scores. Which player had the better year relative to their peers, Perry or Jane? (Note: In general, the lower the ERA, the better the pitcher.)

A student takes a test in his math course and scores 45 points and a test in his psychology courseand scores 71 points. Scores on each test were normally distributed. On the math test the classhas a mean of 40 and a standard deviation of 15. On the psychology test the class has a mean of 75and a standard deviation of 10. On which test did the student do better?

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 student earned a 79 on a precalculus exam, and she earned a 92 on a statistics exam. The precalculus exam had a mean score of 72.3 with a standard deviation of 8.4. On the other hand, the statistics exam had a mean score of 87.4 with a standard deviation of 11.4. Determine which exam the student earned a better score on with respect to her peers.

A different investor decides to invest $8000 in Fund A and $3000 in Fund B. Assuming the amounts gained by the two funds are independent, what are the mean and standard deviation of the amount gained by this investment in the first month?

One year Terry had the lowest ERA (earned-run average, mean number of runs yielded per nine innings pitched) of any male pitcher at his school, with an ERA of 3.02. Also, Karen had the lowest ERA of any female pitcher at the school with an ERA of 3.24. For the males, the mean ERA was 4.364 and the standard deviation was 0.639. For the females, the mean ERA was 3.801 and the standard deviation was 0.959 Find their respective z-scores. Which player had the better year relative to their peers, Terry or Karen? (Note: In general, the lower the ERA, the better the pitcher.) Terry had an ERA with a z-score of Karen had an ERA with a z-score of (Round to two decimal places as needed) Which player had a better year in comparison with their peers? OA. Terry had a better year because of a higher z-score. OB. Karen had a better year because of a lower z-score. OC. Terry had a better year because of a lower z-score. O D. Karen had a better year because of a higher z-score. GIL

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 results of a common standardized test used in psychology research is designed so that the population mean is 175 and the standard deviation is 10. A subject earns a score of 183. What is the z-score for this raw score?