Question

Scores in the first and final rounds for a sample of 20 golfers who competed in tournaments are contained in the Excel Online file below. Construct a spreadsheet to answer the following questions.

Player	First Round	Final Round
Michael Letzig	74	65
Scott Verplank	68	67
D.A. Points	65	72
Jerry Kelly	68	65
Soren Hansen	72	70
D.J. Trahan	72	75
Bubba Watson	67	77
Reteif Goosen	75	69
Jeff Klauk	65	74
Kenny Perry	71	72
Aron Price	67	72
Charles Howell	73	73
Jason Dufner	73	74
Mike Weir	71	77
Carl Pettersson	76	75
Bo Van Pelt	71	71
Ernie Els	77	67
Cameron Beckman	68	66
Nick Watney	74	74
Tommy Armour III	70	69

Suppose you would like to determine if the mean score for the first round of an event is significantly different than the mean score for the final round. Does the pressure of playing in the final round cause scores to go up? Or does the increased player concentration cause scores to come down?

a. Use  to test for a statistically significantly difference between the population means for first- and final-round scores. What is the -value?

-value is  (to 4 decimals)

What is your conclusion?

There _______is ais no significant difference between the mean scores for the first and final rounds.

b. What is the point estimate of the difference between the two population means?

(to 2 decimals)

For which round is the population mean score lower?

_________First roundFinal round

c. What is the margin of error for a 90% confidence interval estimate for the difference between the population means?

(to 2 decimals)

Could this confidence interval have been used to test the hypothesis in part (a)?

_____ (Yes/No)

Explain.

Use the point of the difference between the two population means and add and subtract this margin of error. If zero _______isis not in the interval the difference is not statistically significant. If zero _______isis not in the interval the difference is statistically significant.

Answer 1

Let us denote the difference

d = score for the first round - score for the final round

a)

b) and c)

The point estimate of the difference between the two population means =

For first round, the population mean score is lower.

c) The margin of error for a 90% confidence interval estimate for the difference between the population means = 2.05

ans-> No

Since zero is in the interval the difference is not statistically significant.