Exam Grades \( A \) statistics professor is used to having a variance in his class grades of no more than 100 . He feels that his current group of students is different, and so he examines a random sample of midterm grades (listed below). At \( \alpha=0.01 \), can it be concluded that the variance in grades exceeds 100 ? Assume the variable is normally distribujed. \( \begin{array}{ccccccc}68.7 & 49.1 & 75.8 & 52.8 & 92.3 & 96.7 & 89.4 \\ 65.2 & 69.5 & 72.8 & 67.5\end{array} \) Send data to Excel.

3. Box and Whisker Plot: Draw a box and whisker plot for the data provided and identify any outliers. \( 12,17,13,14,12,16,18,29,15,14,12,17,13,14,12,16,18,29,15,14,12,17,13 \), \[ 14,12,16,18,29,15,14 \]

2. Scatter Plot and Correlation: Consider the following data points representing the number of hours studied \( (x) \) and the marks obtained \( (y) \) : \[ (1,50),(2,55),(3,60),(4,65),(5,75) \] wa scatter plot and determine whether the relationship between hours studied and marks ositive, negative, or none.

What does the magnitude of a correlation coefficient indicate about the variables in a correlational study? Multiple Choice strength of the variables relationship between the variables number of data points

3. Box and Whisker Plot: Draw a box and whisker plot for the data provided and identify any outliers. \( 12,17,13,14,12,16,18,29,15,14,12,17,13,14,12,16,18,29,15,14,12,17,13 \), \( 14,12,16,18,29,15,14 \)

20. Some researchers claim that herbal supplements such as ginseng or ginkgo biloba enhance human memory. To test this claim, a researcher selects a sample of \( n=25 \) college students. Each student is given a ginkgo biloba supplement daily for 6 weeks and then all of the participants are given a standardized memory test. Scores on the normalized test are \( \mu=70 \) and standard deviation of 15 . The sample of 25 students had a mean score of \( M=75 \). (8 points) a. Do the data indicate a significant effect of the herb on memory? Use a two-tailed test with \( \alpha=0.05 \). (Show all steps.)