I have a lab due in my statistics class due tomorrow and i have no idea how to do it. it concerns inference about population means andpopulation proportion.
LAB #3
**Question # 1
In 1990, 5.8% of job applicants who were tested for drugs failed the test. A random sample of 1440 current job applicants results in 61 failures (based loosely on data from the American Management Association). At the α = 0.01 significance level, test the below claim (i.e., that the failure rate is now lower)
HO: p = 0.058
HA: p < 0.058
a) Is this an upper tail, lower tail, or two-tail test? (5 points)
b) Are we testing means or proportions? (5 points)
c) State the rule of rejection (in terms of p-value and level of significance) (5 points)
d) Find the p-value (5 points)
e) Should you reject or not reject HO? (5 points)
f) Does the result suggest that fewer job applicants now use drugs? (5 points)
Question # 2
Researchers studying infant head circumferences (in centimeters) wish to test if the mean head circumference differs from the historical mean of 34.5 cm. The researchers obtain a sample of 17 infants with a mean head circumference of 34.16 cm and a standard deviation of 0.58 cm.
At the α = 0.05 significance level, test the claim
HO: µ = 34.5
HA: µ ≠ 34.5
a) Is this an upper tail, lower tail, or two-tail test? (5 points)
b) Are we testing means or proportions? (5 points)
c) State the rule of rejection (in terms of p-value and level of significance) (5 points)
d) Find the p-value (5 points)
e) Should you reject or not reject HO? (5 points)
f) Does the result suggest that the mean head circumference differs from 34.5 cm? (5 points)
Question # 3
Perform the following hypothesis test on the paired data below:
HO: µd = 0 (Please recall that µd is read ~ and also known as ~ Mu-sub-d)
HA: µd ≠ 0 Test at α = 0.05
Before
30
72
97
59
61
57
57
89
92
After
57
68
98
62
67
71
68
96
98
a) Is this an upper tail, lower tail, or two-tail test? (5 points)
b) Are we testing means or proportions? (5 points)
c) State the rule of rejection (in terms of p-value and level of significance) (5 points)
d) Find the p-value (5 points)
e) Should you reject or not reject HO? (5 points)
f) Do the data provide sufficient evidence to suggest the After scores are indeed higher?
Why or why not? (5 points)
Note: Because the above is a two-tail test, rejection of Ho alone is not a sufficient reason. Hint: What else did you observe among the sample results?
Question # 4
The below sample data represents the cost of 9 name-brand drugs and their corresponding generic equivalent. (Use Name Brand as Sample1)
Name Brand
120
150
135
140
160
175
140
120
165
Generic Brand
99
135
130
119
139
150
129
109
160
a) Compute a two-sided 90% confidence Interval estimate for µd. (5 points)
b) Based on your interval, can you safely conclude that generics are less expensive than name brand? Why or why not? (5 points)
**

Subject | Mathematics |

Due By (Pacific Time) | 04/14/2013 11:00 am |

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