A sample of 25 freshman nursing students made a mean score of 77 on a test designed to measure attitude toward the dying patient. The sample standard deviation was 10. Do these data provide sufficient evidence to indicate, at the .05 level of significance, that the population mean is less than 80? What assumptions are necessary?
Answers
Step-by-step explanation:
For Problems 7−18, please do the following. (a) Draw a scatter diagram displaying the data. (b) Verify the given sums Σx,Σy,Σx2,Σy2, and ∑xy and the value of the sample correlation coefficient r. (c) Find
ˉ
x
,
ˉ
y
,a, and b. Then find the equation of the least-squares line
ˆ
y
=a+bx (d) Graph the least-squares line on your scatter diagram. Be sure to use the point (
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x
,
ˉ
y
) as one of the points on the line. (e) Interpretation Find the value of the coefficient of determination r2. What percentage of the variation in y can be explained by the corresponding variation in x and the least-squares line? What percentage is unexplained? Answers may vary slightly due to rounding. Weight of Car: Miles per Gallon Do heavier cars really use more gasoline? Suppose a car is chosen at random. Let x be the weight of the car (in hundreds of pounds), and let y be the miles per gallon (mpg). The following information is based on data taken from Consumer Reports (Vol. 62, No. 4).
x 27 44 32 47 23 40 34 52
y 30 19 24 13 29 17 21 14
Complete parts (a) through (e), given Σx=299,Σy=167,Σx2=11,887, Σy2=3773,Σxy=5814, and r≈−0.946. (f) Suppose a car weighs x=38 (hundred pounds). What does the leastsquares line forecast for y= miles per gallon?