5 STAT HOMEWORK QUESTIONS

1.

The mean age of all 2564 students at a small university is 22.1 years with a standard deviation of 3.8 years, and the distribution is right-skewed. A random sample of 5 students' ages is obtained, and the mean is 22.6 with a standard deviation of 3.3 years. Complete parts a through c below. a. Find p, cs, 5, and )1. PD FD D x | s=D (Type integers or decimals. Do not round) A random sample of 30 students taking statistics at a community college was asked their cumulative average. The sample mean was 75.31, and the margin of error for a 95% confidence interval was 3.8. Complete parts a and b below. a. Interpret the condence interval. Assume that the conditions for constructing a condence interval are met. Choose the correct answer below and ll in the answer boxes to complete your choice. (Type integers or decimals rounded to the nearest hundredth as needed. Use ascending order.) 0 A. We are 95% condent that the population mean cumulative average for all of the students in the school is between D and D. O B. We are 95% condent that the recorded sample mean cumulative average of statistics students at the school is between D and El. 0 C. We are 95% condent that the population mean cumulative average of statistics students at the school is between D and D. The weights of four randomly chosen bags of horse carrots, each bag labelled 9 kilograms, were 9.4, 9.1, 9.4, and 9.0 kilograms. Assume that the distribution of weights in the population is Normal. Complete parts a through c below. a. Test the hypothesis that the population mean weight is not 9 kilograms. Use a level of signicance of 0.05. Which of the following correctly states H0 and H A? CA. H0429 OB. H0499 0c. H02p=9 State whether each of the following changes would make a confidence interval wider or narrower. (Assume that nothing else changes.) a. Changing from a 90% confidence level to a 95% confidence level b. Changing from a sample size of 20 to a sample size of 350 c. Changing from a standard deviation of 11 kilograms to a standard deviation of 8 kilograms Click the icon to view the t-table. a. How will changing from a 90% confidence level to a 95% confidence level affect the width of the confidence interval? The interval willThe mean length of all 296 songs taken off a band's albumleDs was 3.89 minutes, with a standard deviation of 0.78 minutes. The distribution of song length is right-skewed. The program manager of a radio station wishes to play an uninterrupted block of the band's songs using a random sample of 28 songs from these 296. He nds the mean length of the 28 songs to be 3.81 minutes and the standard deviation of the 28 songs to be 0.93. Complete parts a through c. a. From the problem statement, which of the values 3.89, 0.78, 3.81, and 0.93 are parameters and which are statistics? The value 3.89 is a The value 0.78 is a The value 3.81 is a The value 0.93 is a IEEEE parameter. statistic