In: Statistics and Probability
Increasing numbers of businesses are offering child-care benefits for their workers. However, one union claims that more than 85% of firms in the manufacturing sector still do not offer any child-care benefits. A random sample of 460 manufacturing firms is selected, and only 34 of them offer child-care benefits. Specify the rejection region that the union will use when testing at alpha=.10 include the null and alternate hypothesis
Union claims that more than 85% of firms in the manufacturing sector still do not offer any child-care benefits.
A random sample of 460 manufacturing firms is selected, and only 34 of them offer child-care benefits
Number of manufacturing firms who do not offer any child-care benefits = 460 - 34 = 426
Sample proportion of manufacturing firms who do not offer any child-care benefits = = 426/460 = 0.9261
Sample size = n = 460
Hypothesis :
Right tailed test.
Rejection region :
Given significance level = = 0.1
Critical value for this right tailed test is ,
{ Using Excel, =NORMSINV(0.9) = 1.2816 }
Rejection region = { z : z > 1.2816 }
Test statistic :
Decision about null hypothesis :
It is observed that test statistic (4.571) is greater than critical value (1.2816 )
So reject null hypothesis .
Conclusion :
There is sufficient evidence to support the claim that more than 85% of firms in the manufacturing sector still do not offer any child-care benefits.