Statistics Study Material

STATISTICS
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Question 1
1) 99% confidence interval for p
Sample size = 150
Number of people found disappointed = 35
Proportion = 35/150 =0.233
The z value for 99% confidence interval = 2.5758
Lower limit of 99% confidence interval
Upper limit of 99% confidence interval
99% confidence interval = [0.14438 0.32228]
It can be said with 99% confidence that the sample proportion of people found disappointed
with new Tesla would fall between 0.14438 and 0.32228.
2) Null and alternative hypothesis
Sample proportion of people whose expectation were met p* = (150-35)/150 = 0.76667
The test statistics z is computed as shown below.
The test statistics z comes out 2.99572.
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3) It is a right tailed p value and hence, the p value
The p value = 0.001369
4) Significance level = 0.05
Here, p value is lower than significance level and hence, the null hypothesis will be rejected.
“False”
5) 95% confidence interval
Sample size of Torontonian = 100
Number of Torontonian planned to purchase electric car = 18
P1 = 18/100=0.18
Sample size of Montrealers = 100
Number of Montrealers planned to purchase electric car = 16
P2 = 16/100=0.16
The z value for 95% confidence interval = 2.5758
Now,
Lower limit of 95% confidence interval
Upper limit of 95% confidence interval
95% confidence interval = [0.096 0.304]
It can be said with 95% confidence that the difference of proportion of Torontonian and
Montrealers would fall between 0.14438 and 0.32228.
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