A random sample of 45 salespersons were asked how long, on average, they were able to talk to a potential customer. Their answers revealed a mean of 8.5 minutes with a variance of 9 minutes. If the confidence interval for the population mean is 8.5 * 0.88. What is the probability of selecting a salesperson that doesn't lie within this interval? 0.05 O 0.025 0.95 No correct answer
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- A random sample of 49 statistics examinations was taken. The average score, in the sample, was 85 with a variance of 12.96. What is the 95% confidence interval for the average examination score of the population of the examinations? O 79.00 to 91.00 O 81.40 to 88.60 O 83.97 to 86.03 84.15 to 85.85A health psychologist knew that corporate executives in general have an average score of 2.55 with a standard deviation of 0.5 on a stress inventory and that the scores are normally distributed. In order to learn whether corporate executives who exercise regularly have different stress scores, the psychologist measured the stress of 30 exercising executives and found them to have a mean score of 2.76. a. Using the five steps of hypothesis testing, was the group of 30 exercising executives different from executives in general? (Use the .05 significance level.) Be sure to sketch the distributions involved. Be sure to fully state the five steps and show ALL calculations/work. b. Additionally, explain the logic of what you did to a person who understands hypothesis testing for studies in which the sample consists of a single individual but is unfamiliar with hypothesis testing involving a sample of more than one individual. (Be sure your explanation includes a discussion of the…A pizza delivery chain advertises that it will deliver your pizza in 35 minutes from when the order is placed. Being a skeptic, you decide to test and see if the mean delivery time is actually more than 35 minutes. For the simple random sample of 14 customers who record the amount of time it takes for each of their pizzas to be delivered, the mean is 37.0 minutes with a standard deviation of 9.9 minutes. Assume that the population distribution is approximately normal. Perform a hypothesis test using a 0.05 level of significance. Step 2 of 3: Compute the value of the test statistic. Round your answer to three decimal places.
- A pizza delivery chain advertises that it will deliver your pizza in 2020 minutes from when the order is placed. Being a skeptic, you decide to test and see if the mean delivery time is actually more than 2020 minutes. For the simple random sample of 88 customers who record the amount of time it takes for each of their pizzas to be delivered, the mean is 22.222.2 minutes with a standard deviation of 3.13.1 minutes. Assume that the population distribution is approximately normal. Perform a hypothesis test using a 0.0250.025 level of significance. Step 2 of 3 : Compute the value of the test statistic. Round your answer to three decimal places. Step 3 of 3 : Draw a conclusion and interpret the decision.An analyst is conducting a hypothesis test to determine if the mean time spent on investment research is different from 3 hours per day. The test is performed at the 1% level of significance and uses a random sample of 64 portfolio managers. where the mean time spent on research is found to be 2.7 hours. The population standard deviation is 1.5 hours. What is the value of the test statistic in this case?A herd of 1,500 steers was fed a special high‐protein grain for a month. A random sample of 29 was weighed and had gained an average of 6.7 pounds. If the standard deviation of weight gain for the entire herd is 7.1, test the hypothesis that the average weight gain per steer for the month was more than 5 pounds. What assumptions did you make in selecting the test statistic?
- A recent survey of 8 social network sites has a mean of 13.1 million visitors for a specific month. The standard deviation was 4.1 million. Find the 95% confidence interval of the true mean.A group of 30 randomly selected students have a mean score of 24.6 with a standard deviation of 3.3 on a placement test. What is the 95% confidence interval for the mean score, μ, of all students taking the testA pizza delivery chain advertises that it will deliver your pizza in 35 minutes from when the order is placed. Being a skeptic, you decide to test and see if the mean delivery time is actually more than 35 minutes. For the simple random sample of 14 customers who record the amount of time it takes for each of their pizzas to be delivered, the mean is 37.0 minutes with a standard deviation of 9.9 minutes. Assume that the population distribution is approximately normal. Perform a hypothesis test using a 0.05 level of significance. Step 1 of 3: State the null and alternative hypotheses for the test. Fill in the blank below. Ho: 35 Họ 1 = H₂H = 35
- A pizza delivery chain advertises that it will deliver your pizza in 25 minutes from when the order is placed. Being a skeptic, you decide to test and see if the mean delivery time is actually more than 25 minutes. For the simple random sample of 11 customers who record the amount of time it takes for each of their pizzas to be delivered, the mean is 27.7 minutes with a standard deviation of 2.9 minutes. Assume that the population distribution is approximately normal. Perform a hypothesis test using a 0.10 level of significance. Step 1 of 3: State the null and alternative hypotheses for the test. Fill in the blank below. Ho : µ = 25 25 Answer 国 Tables 国 Keypad Keyboard Shortcuts Oa group of 59 randomly selected students have a mean score of 29.5 with a standard deviation of 5.2 on a placement test. what is the 90% confidence interval for the mean score, u, of all students taking the test?A pizza delivery chain advertises that it will deliver your pizza in 35 minutes from when the order is placed. Being a skeptic, you decide to test and see if the mean delivery time is actually more than 3535 minutes. For the simple random sample of 15customers who record the amount of time it takes for each of their pizzas to be delivered, the mean is 40.4 minutes with a standard deviation of 7.4 minutes. Assume that the population distribution is approximately normal. Perform a hypothesis test using a 0.10 level of significance. Step 3 of 3 : Draw a conclusion and interpret the decision.