Question

An exercise science major wants to try to use body weight to predict how much someone can bench press. He collects the data shown below on 30 male students. Both quantities are measured in pounds. Assignment 10q3 data a) What type of association does there appear to be between these two variables? negative association can not be determined no association positive association b) Compute a 95% confidence interval for the average bench press of 150 pound males. What is the lower limit? Give your answer to two decimal places. X c) Compute a 95% confidence interval for the average bench press of 150 pound males. What is the upper limit? Give your answer to two decimal places. d) Compute a 95% prediction interval for the bench press of a 150 pound male. What is the lower limit? Give your answer to two decimal places. e) Compute a 95% prediction interval for the bench press of a 150 pound male. What is the upper limit? Give your answer to two decimal places.

Body weight	Bench press
148	145
176	148
154	133
189	156
181	166
217	174
210	168
150	139
137	109
151	119
172	138
219	167
142	131
143	119
164	151
136	124
147	149
129	134
219	162
169	140
180	149
187	156
198	149
156	131
220	149
154	138
212	147
122	122
163	133
136	136

Answer 1

Applying regression from megastat:

Regression output					confidence interval
variables	coefficients	std. error	t (df=28)	p-value	95% lower	95% upper
Intercept	70.1712	10.3998	6.747	2.51E-07	48.8682	91.4742
Body weight	0.4284	0.0605	7.082	1.05E-07	0.3045	0.5524
Predicted values for: Bench press
		95% Confidence Interval		95% Prediction Interval
Body weight	Predicted	lower	upper	lower	upper	Leverage
150	134.44	130.07	138.80	113.97	154.90	0.05

b)

lower limit =130.07

c)

upper limit =138.80

d)

lower limit =113.97

e)

upper limit =154.90