Given: (Equation population regression line):
The average height of 15-year-old students at this high scool according to the population regression line can be found by replacing x in the regression line equation by 15 and evaluating. Thus the mean is 168 and the standard deviation is7. Since the conditions are met, the response y varies according to a Normal distribution. The z-score is the value decreased by the mean, divided by the standard deviation. Determine the corresponding probability using the normal probability table in the appendix. is given in the row starding with 1.7 and in the column starting with .01 of the standard normal probability table in the appendix.
Thus about of the 15-year-old students at this scool are expected to be taller than 180 cm.
Unusual points Each of the four scatterplots that follow shows a cluster of points and one “stray” point. For each, answer these questions:
1) In what way is the point unusual? Does it have high leverage, a large residual, or both?
2) Do you think that point is an influential point?
3) If that point were removed, would the correlation be- come stronger or weaker? Explain.
4) If that point were removed, would the slope of the re- gression line increase or decrease? Explain
Make a scatterplot of the data and graph the function
Make a scatterplot for each set of data.