A customer service department asks its customers to rate their​ over-the-phone service on a scale of​ 1-20 immediately after their service has been completed. The department then matches each​ customer's rating with the number of minutes the person waited on hold. The accompanying table shows the ratings and number of minutes on hold for 10 randomly selected customers. Minutes Rating   4 16   8 12   1 17   6 10   7 13   1 17   10 15   3 19   7 15   3 13   R2=0.274   α=0.05​   The ​F-test statistic is 3.02. The​ p-value is 0.121 ​   Because the​ p-value is greater than α​, do not reject the null hypothesis. There is not enough evidence to conclude that the coefficient of determination is significant.   c. Construct a​ 95% confidence interval for the average rating given by a customer who waits 8 minutes.   UCL = 15.88 ​(Round to two decimal places as​ needed.) LCL = 10.74 ​(Round to two decimal places as​ needed.)   d. Construct a​ 95% prediction interval for the rating given by a customer who waits 8 minutes.   UPL =   ​(Round to two decimal places as​ needed.) LPL =   ​(Round to two decimal places as​ needed.)

The numbers of polio cases in the world are shown in the table for various years. Year Number of Polio Cases (thousands) 1988 1992 1996 2000 2005 2007 350 138 33 3 3.2 1.3 Let f(t) be the number of polio cases (in thousands) t years after 1980. Copy the data to Desmos to draw a scatterplot of the data. Make sure to adjust the years so they represent years after 1980. a) Is it better to model the data with a linear or with an exponential model? [Select an answer b) Use regression in Desmos to find an appropriate model for f. Make sure to check Log mode in the parameter window in Desmos if you are fitting an exponential model. f(t) Round the coefficients to 4 decimal places. Hint: Use the variablet from the drop down menu when entering the equation. Do not just type in t. c) Predict the number of polio cases in 2013. d) Find the approximate half-life of the number of polio cases. Round the answer to one decimal place. years

The data set below represents the ages of 36 executives. Find the percentile that corresponds to an age of 41 years old. 28 29 30 31 32 33 33 35 35 35 36 39 39 39 40 40 41 41 43 44 55 57 58 59 53 63 47 48 52 53 54 60 62 62 64 64 量重 重 Percentile of 41 = (Round to the nearest integer as needed.) Textbook Calculator Next 7:39 PM O Type here to search 33 70°F Cloudy ^ 1 4) 10/8/2021 23 Lenovo XL-BT 10/05/17 Esc PrtSc Insert Delete F1 F3 F4 F5 F6 F7 F8 F9 F10 F11 F12 %23 & Backspace Num Lock 3 4 5 7 T Y U 8O Tab C Home PgUp A F G H. CapsLk Enter C V B N 2 Shift End PgUp Fn Alt Alt Ctrl Home End Co の * 00 MN ( CO

OL th.. Frequency 8 9 0 T 10 20 30 40 LEAD 50 60 70 80 Data were collected on the lead levels of children of battery factory workers. The data are displayed in the histogram above. Choose the correct answer. The maximum lead level is less than 60 The median lead level (the level that exactly half the children exceed) is less than 30 There are 33 children in the data set. None of the other answers is true

Compute this measure of central tendency and explain what this means in everyday language. The frequency table is given as: X Frequency proportion percent 0 7 0.35 35% 1 4 0.20 20% 2 3 0.15 15% 3 2 0.10 10% 5 1 0.05 5% 7 1 0.05 5% 8 1 0.05 5% 9 1 0.05 5% Total 20 1 100%

Q.8