Hypothesis Test and Confidence Interval for One Mean
1. A report by the Gallup Poll found that a woman visits her
doctor, on average, at most 5.8 times each year. A random sample of
20 women results in these yearly visit
totals.
Data: 4; 2; 1; 3; 7; 2; 9; 4; 6; 6; 7; 0; 5; 6; 4; 2; 1; 3; 4;
2
a. At the α = 0.05 level can it be concluded that the
sample mean is higher than 5.8 visits per year?
α = Ho: Ha: |
T – Test inpt: Data Stats µ0: List: Freq:1 µ ≠ µ0< µ0 > µ0 Calculate |
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T – Test µ0: t = p= x: sx : n: |
Decision: Compare the p-value with alpha and give your decision. |
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Conclusion: |
b. Find a 95 % confidence interval of the true mean years visits of a woman to her doctor.
TInterval Inpt: Data Stats x: sx : n: C-Level: . Calculate |
T-Interval ( , ) x: sx : n: |
||
Conclusion: We are 95% Confident…… |
Here Mean
Standard deviation s=
a. Here Alpha 0.05
As it is asked sample mean is higer than 5.8 visits per year and
Now t-value
=
now p-value
P value = TDIST (t statistics, df, tails)=0.0010
As p-value is smaller than alpha=0.05 we reject the null hypothesis.
b.For 95% confidence interval t-value=
TINV(0.05,19)= |
t-value=2.093
Margin or error
Margin of error | 1.114 | ||
Confidence interval | 2.786 | 5.014 |
We are 95% confident that population mean will lie between 2.786 and 5.014.
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