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Homework 4
1. The brain volumes (
) of 24 brains have a mean of 1,236.5 cm3 and a standard deviation of 178 cm3. For such data, Brain volume of lesser than what would be significantly (or unusually) low?
2. The blood platelet counts of a group of women have a uniform distribution with a mean of 285.2 and a standard deviation of 23.8. What is the approximate percentage of women with (or at least what percentage of women have) platelet counts within two standard deviations of the mean?
3. The body temperatures of a group of healthy adults have a skewed distribution with a mean of 98.75 oF and a standard deviation of 0.11 oF. What is the approximate percentage of body temperatures (or at least what percent of body temperatures are) within three standard deviations of the mean?
4. The mean height of a basketball team is 6.1 feet with a standard deviation of 3.4 feet. The team’s center is 5.6 feet tall. Find the center’s z score.
5. A test score of 56 on a test having a mean of 67 and a standard deviation of 5. Determine if the value is unusual. Explain. Enter the number that is being interpreted to arrive at your conclusion rounded to the nearest hundredth.
6. Use the given sample data to find Q3.
41, 54, 69, 53, 44, 67, 52, 60
7. Find the percentile for the data value.
Data set: 3, 18, 7, 25, 2, 10, 17;
data value: 7
8. Which is better, a score of 91 on a test with a mean of 71 and a standard deviation of 9, or a score of 255 on a test with a mean of 242 and a standard deviation of 25? Enter the better test score.
9. The test scores of 16 students are listed below. Construct a boxplot for the data set. Enter the maximum value.
46, 5, 14, 8, 3, 35, 104, 89, 80, 61, 44, 81, 18, 66, 79, 29
Homework 4 Answers
1. The blood platelet counts of a group of women have a uniform distribution with a mean of 285.2 and a standard deviation of 23.8. What is the approximate percentage of women with (or at least what percentage of women have) platelet counts within two standard deviations of the mean?
Answer: 75