In: Statistics and Probability
Since an instant replay system for tennis was introduced at a major tournament, men challenged 13861386 referee calls, with the result that 427427 of the calls were overturned. Women challenged 763763 referee calls, and 224224 of the calls were overturned. Use a 0.010.01 significance level to test the claim that men and women have equal success in challenging calls. Complete parts (a) through (c) below. a. Test the claim using a hypothesis test. Consider the first sample to be the sample of male tennis players who challenged referee calls and the second sample to be the sample of female tennis players who challenged referee calls. What are the null and alternative hypotheses for the hypothesis test? A. Upper H 0H0: p 1p1equals=p 2p2 Upper H 1H1: p 1p1less than
p 2p2 E. Upper H 0H0: p 1p1greater than or equals≥p 2p2 Upper H 1H1: p 1p1not equals≠p 2p2 F. Upper H 0H0: p 1p1not equals≠p 2p2 Upper H 1H1: p 1p1equals=p 2p2 Identify the test statistic. zequals=nothing (Round to two decimal places as needed.) Identify the P-value. P-valueequals=nothing (Round to three decimal places as needed.) What is the conclusion based on the hypothesis test? The P-value is ▼ greater than less than the significance level of alphaαequals=0.010.01, so ▼ fail to reject reject the null hypothesis. There ▼ is not sufficient is sufficient evidence to warrant rejection of the claim that women and men have equal success in challenging calls. b. Test the claim by constructing an appropriate confidence interval. The 9999% confidence interval is nothingless than
Ho: p1 - p2 = 0
Ha: p1 - p2 ╪ 0
sample #1 -----> male
first sample size, n1=
1386
number of successes, sample 1 = x1=
427
proportion success of sample 1 , p̂1=
x1/n1= 0.3081
sample #2 -----> female
second sample size, n2 =
763
number of successes, sample 2 = x2 =
224
proportion success of sample 1 , p̂ 2= x2/n2 =
0.2936
difference in sample proportions, p̂1 - p̂2 =
0.3081 - 0.2936 =
0.0145
pooled proportion , p = (x1+x2)/(n1+n2)=
0.3029
std error ,SE = =SQRT(p*(1-p)*(1/n1+
1/n2)= 0.0207
Z-statistic = (p̂1 - p̂2)/SE = (
0.015 / 0.0207 )
= 0.70
p-value =
0.4839 [excel formula =2*NORMSDIST(z)]
decision : p-value>α,Don't reject null
hypothesis
fail to reject the null hypothesis
There ▼ is not sufficient evidence to warrant rejection of the claim that women and men have equal success in challenging calls
b)
level of significance, α = 0.01
Z critical value = Z α/2 =
2.576 [excel function: =normsinv(α/2)
Std error , SE = SQRT(p̂1 * (1 - p̂1)/n1 + p̂2 *
(1-p̂2)/n2) = 0.0206
margin of error , E = Z*SE = 2.576
* 0.0206 = 0.0531
confidence interval is
lower limit = (p̂1 - p̂2) - E = 0.015
- 0.0531 = -0.0386
upper limit = (p̂1 - p̂2) + E = 0.015
+ 0.0531 = 0.0676
so, confidence interval is (
-0.0386 < p1 - p2 <
0.0676 )