A teller at a drive-up window at a bank had the following service times (in minutes) for 20 randomly selected customers: SAMPLE 1 2 3 4 4.54.64.54.7 4.24.54.64.6 4.24.44.44.8 4.34.74.44.5 4.34.34.64.9 If the process parameters are unknown, estimate its mean and standard deviation. (That is, find the average and standard deviation of all data points at once.) Select one: a. x_bar = 4.7, s = 0.19 b. x_bar = 4.3, s= 0.0368 c. x_bar = 4.5, s = 0.0368 O d. x_bar = 4.5, s = 0.19 None of the other options. x_bar = 4.7, s = 0.0368 x_bar = 4.3, s = 0.19 e. f. g.

A random sample of 8 adults aged 30 years were asked how much they spent on medical costs in the year 2009. Using the following data, compute the sample mean, the sample standard deviation, the sample median, and the first and third quartiles. 300 140 5600 520 470 700 640 1200

n a school district, all sixth grade students take the same standardized test. The superintendant of the school district takes a random sample of 21 scores from all of the students who took the test. She sees that the mean score is 128 with a standard deviation of 41.4416. The superintendant wants to know if the standard deviation has changed this year. Previously, the population standard deviation was 25. Is there evidence that the standard deviation of test scores has increased at the α=0.005 level? Assume the population is normally distributed. Step 1 of 5 :  State the null and alternative hypotheses. Round to four decimal places when necessary.

Esp Heavy children: Are children heavier now than they were in the past? The National Health and Nutrition Examination Survey (NHANES) taken between 1999 and 2002 reported that the mean weight of six-year-old girls in the United States was 49.3 pounds. Another NHANES survey, published in 2008, reported that a sample of 193 six-year-old girls weighed between 2003 and 2006 had an average weight of 52 pounds. Assume the population standard deviation is o =16 pounds. Can you conclude that the mean weight of six-year-old girls in 2006 is different from what it was in 2002? Use the a =0.01 level of significance and the critical value method. 00 Part: 0/ 5 Part 1 of 5 (a) State the appropriate null and alternate hypotheses. H.: OD O=0 dl. H : This hypothesis test is a (Choose one) test. 00

find the actual percentage in the data set, sort the DRIVE variable and count how many of the data points are less than 25 out of the total 35 data points. That is the actual percentage. How does this compare with your prediction? Mean: 57.457 Standard deviation: 26.539 Predicted percentage: 0.110 Drive: 44 20 88 6 71 42 76 63 61 63 84 28 55 33 88 80 86 83 5 85 25 25 54 54 81 73 29 76 78 77 42 65 71 94 6

A sample of underweight babies was fed a special diet and the following weight gains (lbs.) were observed at the end ofthree months.6.7 5.8 4.8 3.6 4.7 4.6 5.2 5.9 4.5The mean and standard deviation respectively are:a. 5.09, 0.92 b. 5.1, 0.87 c. 5.08, 8.7 d. 5.09, 0.87 e. none of these

The ages of undergraduate students at two universities (one in the east and one in the west) are being compared.  Researchers want to know if there is a difference in the mean age of students at the two universities.  The population standard deviations are known. The following data shows the results of samples collected at each institution:              School Location       n (sample size)        sample mean ( )         population standard deviation              West                      33                           25.78                       6.29              East                       35                           23.16                       7.52   What is the value of the test statistic for the previous problem?  (Enter your answer as a positive value even if you calculated a negative test statistic value i.e. if you calculated -1.311 you should enter 1.311).  Round your answer to 3 decimal places.