9.4.15
2 answers:
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We have the sample size, sample mean and the sample standard deviation. Since the population standard deviation is not know, we will use t-distribution to find the confidence interval.
The critical t value for 95% confidence interval and 63 degrees of freedom is 1.998.
The 95% confidence for the population mean will be:
Thus, the 95% confidence interval for the population mean will be (115,123)
So, option A is the correct answer
The critical t value for 95% confidence interval and 63 degrees of freedom is 1.998.
The 95% confidence for the population mean will be:
Thus, the 95% confidence interval for the population mean will be (115,123)
So, option A is the correct answer
Answer:
His 95% confidence interval is (0.065, 0.155).
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of , and a confidence level of
, we have the following confidence interval of proportions.
In which
z is the zscore that has a pvalue of .
For this problem, we have that:
95% confidence level
So , z is the value of Z that has a pvalue of
, so
.
The lower limit of this interval is:
The upper limit of this interval is:
His 95% confidence interval is (0.065, 0.155).