Question

1. A researcher wants to know if the typing speed of a secretary in words per minute is related to the time in hours that it takes to learn the new word processing program. Below is speed versus hours to learn program. Find the standard error of estimate for an average secretary who has a typing speed of 72 words per minute to learn the word processing program.

2. A researcher wants to know if the typing speed of a secretary in words per minute is related to the time in hours that it takes to learn the new word processing program. Below is speed versus hours to learn program. Find the 90 % prediction interval for number of hours it would take an average secretary who has a typing speed of 72 words per minute to learn the word processing program.

Typing speed --48- 74 - 52- 79-- 83- 56- 85- 63- 88- 74- 90- 92
Time hrs.----- --7- ---4--- 8 - 3.5----2 - 6 --2.3- 5 - 2.1- 4.5-1.9- 1.5

Answer 1

1. The standard error of estimate = 0.513

2. The 90% prediction interval for number of hours it would take an average secretary who has a typing speed of 72 words per minute to learn the word processing program is between 3.2430 and 5.1808.

Typing speed	Time hrs.
48	7
74	4
52	8
79	3.5
83	2
56	6
85	2.3
63	5
88	2.1
74	4.5
90	1.9
92	1.5

	r²	0.949
	r	-0.974
	Std. Error	0.513
	n	12
	k	1
	Dep. Var.	Time hrs.
ANOVA table
Source	SS	df	MS	F	p-value
Regression	49.0214	1	49.0214	186.02	8.69E-08
Residual	2.6353	10	0.2635
Total	51.6567	11
Regression output				confidence interval
variables	coefficients	std. error	t (df=10)	p-value	90% lower	90% upper
Intercept	14.0857
Typing speed	-0.1371	0.0101	-13.639	8.69E-08	-0.1554	-0.1189
Predicted values for: Time hrs.
		90% Confidence Interval	90% Prediction Interval
Typing speed	Predicted	lower	upper	lower	upper	Leverage
72	4.2119	3.9416	4.4822	3.2430	5.1808	0.084