General Direction: Read and follow the instructions carefully.

Directions: Choose the letter that corresponds to the correct answer.

16) Which of the following illustrates confidence level? a. 90% O b. 32.8 O c. 30-39 d. 90% - 94% 17) Given: n = 80, x = 76.5, s= 3.1. Which of these is the point estimate of the population mean? a. 3.1 O b. 76.6 O c. 80 O d. 8.9 For numbers 18-20: The mean gasoline consumption of 10 cars is 28 liters with a standard deviation 1.6 liters. Find the point and the interval estimates using 95% confidence level. 18) What is the point estimate of ? O a. 28 O b. 95% O c. V10 O d. 1.6 19) What is the appropriate distribution? a. t Ob. p O C. S O d. z 20) What are the confidence coefficients? O a. +2.58 O b. +1.96 O c. $2.26 O d. +2.3310) The is a range of values that contains the parameter value. a. Confidence limits b. Confidence interval c. Confidence coefficient d. Confidence level 11) What do we call the probability that a parameter is contained in a range of values? a. Confidence interval b. Confidence level c. Confidence coefficient d. Confidence limit 12) Which of the following are the 95% confidence coefficients? O a. +2.33 O b. + 2.58 O c. +1.96 O d. +1.645 13) The maximum error of the estimate is found by a. multiplying Za by standard deviation of the sample means O b. C. subtracting Za by standard deviation of the sample means O d. adding Za by standard deviation of the sample means 14) Given n = 50, o = 1.2, and a = 0.1. The maximum error E is approximately: a. none of these b. 0.44 O c. 0.39 O d. 0.330 15) What is the value resulting from subtracting the maximum error from the sample mean? O a. Point estimate b. Lower limit of the interval estimate O C. Upper limit of the interval O d. Interval estimate5) If the variance of the population is 10, what is the variance of the sampling distribution of the means of size 5 drawn from this population? O a. 1.41 O b. 10 O c. 4.47 O d. 2 6) Which sample size will give a smaller standard error of the mean? O a. 12 b. 35 O c. 20 O d. 25 For numbers 7-9, refer to the problem below. The average precipitation for the first 7 months of the year is 19.32 inches with a standard deviation of 2.4 inches. Assume that the average precipitation is normally distributed. 7) What is the probability that a randomly selected year will have precipitation greater than 18 inches for the first 7 months? a. 0.7088 b. 0.4562 O c. 0.1258 O d. 0.8523 8) What is the average precipitation of 5 randomly selected years for the first 7 months? a. 15.56 inches b. 20.52 inches O c. 19.32 inches d. 22.4 inches 9) What is the probability of 5 randomly selected years will have an average precipitation greater than 18 inches for the first 7 months? a. 0.2587 b. 0.4156 c. 0.2879 O d. 0.89071) Which of the following statements is correct? a. The mean of the sampling distribution of the means is less than the population mean. b. The means of the samples drawn from a population are always equal to the population mean. c" The means of the samples drawn from a population may be equal, greater than or less than the population mean. d' The mean of the sampling distribution of the sample means is greater than the population mean. 2) A certain population has a mean of 15.4 and a standard deviation of 5.6. If random samples size 5 is taken from this population, which of the following statements is correct. a. The mean of the sampling distribution of the sample means is equal to 15.4. b' The standard deviation of the sampling distribution of the sample means is 5.6. c. The standard deviation of the sampling distribution of the sample means is 15.4. d' The mean of the sampling distribution of the sample means is less than 15.4 3) How many possible of size n = 3 can be drawn from a population of size 12? a. 144 b. 220 c. 1728 d. 36 4.) What is the shape of the sampling distribution of the means if random samples of size n become larger. a. right skewed b. normal c. left skewed d. rectangular