A random sample of 25 items is selected from a population. When computing a conf
ID: 3362407 • Letter: A
Question
A random sample of 25 items is selected from a population. When computing a confidence interval for the population mean when the population standard deviation is not known, what test statistic should you use?
A.
A t-value with 24 degrees of freedom
B.
A t-value with 25 degrees of freedom
C.
A Z-value since we know the population mean.
D.
A X-value because the population is normally distributed.
Suppose a research has a sample of 5 from a population with unknown standard deviation but a known mean. What approach should be used to test if the sample actually comes from the population?
Use a z-score and assume that that data is normal
Use a t-score but do not worry if the data is normal since the sample is sufficiently small to assume normality.
Use an f-score and assume the data is skewed
Use a t-score but test the data to determine if the data can reasonably be assumed normal.
A.Use a z-score and assume that that data is normal
B.Use a t-score but do not worry if the data is normal since the sample is sufficiently small to assume normality.
C.Use an f-score and assume the data is skewed
D.Use a t-score but test the data to determine if the data can reasonably be assumed normal.
Explanation / Answer
1) A. .A t-value with 24 degrees of freedom
Since the population standard deviation is not known. df = N-1 = 25-1 = 24
Use a t-score but test the data to determine if the data can reasonably be assumed normal.
2) D.Use a t-score but test the data to determine if the data can reasonably be assumed normal.
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