2. Calculate the mean and standard deviation for the following distribution. Draw the distribution curve and check whether the curve is normal or skewed. f- frequency Class 4.5-12.5 4 12.5-20.5 24 20.5-28.5 21 28.5-36.5 18 36.5-44.5 44.5-52.5 3 52.5-60.5 5

3)   What graphs can help us identify a normal distribution? a. Dotplot b. Histogram c. Boxplot d. Normal probability plot pick one      a, b, c, d     b, c     a, b     a, b, c     b, d

2. Which of the following graphs represent a normal distribution? Chart A 20 15 10 (1, 5.4) (5.4, 9.8) (9.8, 14.2) (14.2, 18.6) (18.6, 23] (23, 27.4] Chart B 19 0.5 Category 1 Category 2 Category 4 Chart C 20 [1, 6) 16. 111 (11, 16] (16, 21] (21, 26] Chart D 25 15 10 (1,7.4) (74, 13.8) (13.8, 20.2) (20.2, 26.6]

The amount of coffee that people drink per day is normally distributed with a mean of 17 ounces and a standard deviation of 6 ounces. 11 randomly selected people are surveyed. Round all answers to 4 decimal places where possible.

It is commonly believed that the mean body temperature of a healthy adult is 98.6° F. You are not entirely convinced. You believe that it is higher than 98.6° F. The temperatures for 12 randomly selected healthy adults are shown below. Assume that the distribution of the population is normal. 100.1, 96.8, 98.7, 100, 99.1, 98.3, 97.5, 100.9, 99.1, 100, 98.1, 100.1 What can be concluded at the a = 0.05 level of significance? a. For this study, we should use Select an answer b. The null and alternative hypotheses would be: Ho: ? Ha: Select an answer Select an answer c. The test statistic O Question Help: (please show your answer to 3 decimal places.) (Please show your answer to 4 decimal places.) d. The p-value = e. The p-value is a f. Based on this, we should Select an answer the null hypothesis. g. Thus, the final conclusion is that ... There is sufficient evidence to conclude that the population mean body temperature for healthy adults is higher than 98.6° F. There is not sufficient…

The following frequency distribution represents the time in seconds of a fast-food drive-thru service at a specific location on a given day. Time Frequency 65 - 95.4 1 95.5 - 125.9 126 - 156.4 10 156.5 - 186.9 28 187 - 217.4 37 217.5 - 247.9 18 248 - 278.4 A. Identify the type of distribution. B. Find the mean and the standard deviation of the time of the drive-thru service

39

9 The weights for a group of​ 18-month-old girls are normally distributed with a mean of 24.7pounds and a standard deviation of 2.2 pounds. Use the given table to find the percentage of​ 18-month-old girls who weigh between 22.2 and 23.1 pounds.   ​z-score ​-3.0 ​-2.9 ​-2.8 ​-2.7 ​-2.6 ​-2.5 ​-2.4 ​-2.3 ​-2.2 ​-2.1 Percentile 0.13 0.19 0.26 0.35 0.47 0.62 0.82 1.07 1.39 1.79 ​z-score ​-2.0 ​-1.9 ​-1.8 ​-1.7 ​-1.6 ​-1.5 ​-1.4 ​-1.3 ​-1.2 ​-1.1 Percentile 2.28 2.87 3.59 4.46 5.48 6.68 8.08 9.68 11.51 13.57 ​z-score ​-1.0 ​-0.9 ​-0.8 ​-0.7 ​-0.6 ​-0.5 ​-0.4 ​-0.3 ​-0.2 ​-0.1 Percentile 15.87 18.41 21.19 24.20 27.43 30.85 34.46 38.21 42.07 46.02   ________​% of​ 18-month-old girls weigh between 22.2 and 23.1 pounds. ​(Round the final answer to the nearest hundredth as needed. Round the​ z-score to the nearest tenth as​ needed.)

what proportation of a normal distribution is located between each of the following z-score boundaries? a. z=-1.64 and z=+1.64 b. z=-1.96 and z=+1.96 c. z=-1.00 and z=+1.00

Suppose that a committee is studying whether or not there is waste of time in our judicial system. It is interested in the mean amount of time individuals waste at the courthouse waiting to be called for jury duty. The committee randomly surveyed 81 people who recently served as jurors. The sample mean wait time was 8 hours with a sample standard deviation of 4.6 hours. 1. Which distribution should you use for this problem? Explain your choice. a. The standard Normal distribution should be used because the population standard deviation is known. b. The Student's tt-distribution for 81 degrees of freedom should be used because we do not know the population    standard deviation. c. The Student's tt-distribution for 80 degrees of freedom should be used because we do not know the population standard deviation. d. The standard Normal distribution should be used because the sample standard deviation is known.\   2. Construct a 95% confidence interval for the…