Question

The data below are the temperatures on randomly chosen days during a summer class and the number of absences on those days:

      Temperature, x | 72 85 91 90 88 98 75 100 80  
No. of absences, y |   3     7 10 10    8 15 4    15 5


a) Find the equation of the regression line for the data.

b)  Assuming that the variables x and y have a significant correlation,
what is the predicted number of absences when the temperature is 91?

c) Calculate the correlation coefficient.

d) Calculate the standard error for the model.

Answer 1

(a) The equation of the regression line is:

y = -30.2677 + 0.4485*x

(b) y = -30.2677 + 0.4485*91 = 10.55

(c) r = 0.980

(d) The standard error for the model is 0.934.

	r²	0.960
	r	0.980
	Std. Error	0.934
	n	9
	k	1
	Dep. Var.	y
ANOVA table
Source	SS	df	MS	F	p-value
Regression	148.1166	1	148.1166	169.81	3.65E-06
Residual	6.1056	7	0.8722
Total	154.2222	8
Regression output				confidence interval
variables	coefficients	std. error	t (df=7)	p-value	95% lower	95% upper
Intercept	-30.2677
x	0.4485	0.0344	13.031	3.65E-06	0.3671	0.5299