The average salary of 64 employee was 5400. Using historical data, we will assume that the population standard deviation is 260. Find the 90% confidence interval for the population mean salary. Select one: O a. 5400 + 53.46 O b. 5400 + 57.58 Oc. 5400 + 55.52 O d. 5400 + 51.41

Assume that the population has a normal distribution.Thirty randomly selected students took the statistics final. If the sample mean was 93 and the standard deviation was 6.6, construct a 99% confidence interval for the mean score of all students. Interpret the results.

You would like to estimate the variance and standard deviation for credit scores based on FICO.  These scores are thought to be normally distributed.  You randomly select 36 credit scores to get a standard deviation of 56.5.  Using a 95% confidence interval, estimate the variance and standard deviation of credit scores.

1.3

Calculate the mean and standard deviation from the following data : 60-69 Value: 90-99 80-89 70-79 50-59 40-49 30-39 Frequency: 12 22 20 14 4.

For a sample of 23 operating rooms taken in a hospital study, the mean noise level was 37.9 decibels, and the standard deviation was 7.6. Find the 95% confidence interval of the true mean of the noise levels in the operating rooms. Assume the variable is normally distributed. Use a graphing calculator and round the answers to at least one decimal place.

Pyramid Lake is on the Paiute Indian Reservation in Nevada. The lake is famous for cutthroat trout. Suppose a friend tells you that the average length of trout caught in Pyramid Lake is ? = 19 inches. However, a survey reported that of a random sample of 51 fish caught, the mean length was x = 18.6 inches, with estimated standard deviation s = 2.9 inches. Do these data indicate that the average length of a trout caught in Pyramid Lake is less than ? = 19 inches? Use ? = 0.05. i-What is the value of the sample test statistic? (Round your answer to three decimal places.)

Tina catches a 14-pound bass.  She does not know the population mean or standard deviation.  So she takes a sample of five friends and they say the last bass they caught was 9, 12, 13, 10, and 10 pounds.  Find the t and calculate a 95% (α = .05) confidence interval.

Use z scores to compare the given values. The tallest living man at one time had a height of 238 cm. The shortest living man at that time had a height of 142.4 cm. Heights of men at that time had a mean of 175.45 cm and a standard deviation of 5.59 cm. Which of these two men had the height that was more extreme? ... Since the z score for the tallest man is z = 0 and the z score for the shortest man is z = the man had the height that was Im- more extreme. (Round to two decimal places.) shortest tallest

Pyramid Lake is on the Paiute Indian Reservation in Nevada. The lake is famous for cutthroat trout. Suppose a friend tells you that the average length of trout caught in Pyramid Lake is ? = 19 inches. However, a survey reported that of a random sample of 46 fish caught, the mean length was x = 18.4 inches, with estimated standard deviation s = 2.7 inches. Do these data indicate that the average length of a trout caught in Pyramid Lake is less than ? = 19 inches? Use ? = 0.05. Solve the problem using the critical region method of testing (i.e., traditional method). (Round the your answers to three decimal places.)   test statistic =   critical value =   State your conclusion in the context of the application. Reject the null hypothesis, there is sufficient evidence that the average fish length is less than 19 inches.Reject the null hypothesis, there is insufficient evidence that the average fish length is less than 19 inches.    Fail to reject the null hypothesis, there is…