Reference no: EM132845701
Lab Assignment: Midterm 1 Review
Imagine the following random sample of scores on an exam (# correct out of 20 points). The investigator wants to describe the sample of scores.
9 13 16 20 12 12
1. Calculate the mean, median, and mode of the distribution of scores.
2. Calculate the range and interquartile range of the distribution of scores.
3. Draw a boxplot to represent this information (make sure to include the mean).
4. Calculate the appropriate index of standard deviation.
5. What does the standard deviation tell us about the scores on the exam?
6. IQ scores have a mean of 100 and standard deviation of 15. What is the probability that a person has an IQ of 90 or above?
7. As noted above, IQ scores have a population mean of 100 and standard deviation of 15. What is the probability that a randomly selected classroom of 20 students will have a mean IQ of 105 or greater?
8. A sample of 15 students was collected to estimate the mean number of hours the student body spends in the library each week. The mean of the sample was 4.6 hours, and the standard deviation was 1.2 hours. Construct a 95% confidence interval around this sample mean.
9. Describe a sentence interpreting this confidence interval.
10. A student in one section of a statistics class scores a 76 on an exam, where the mean was 70 and the standard deviation was 4. A second student in a different section of a statistics class scored an 85 on an exam, where the mean was 84, and the standard deviation was 2. Which student did worse on the exam?