In: Statistics and Probability
To test Upper H 0: mu equals 50 versus Upper H 1: mu less than 50, a random sample of size n equals 22 is obtained from a population that is known to be normally distributed. Complete parts (a) through (d) below. LOADING... Click here to view the t-Distribution Area in Right Tail. (a) If x over bar equals 47.1 and s equals 12.9, compute the test statistic. t 0 equals nothing (Round to three decimal places as needed.)
Solution:-
State the hypotheses. The first step is to state the null hypothesis and an alternative hypothesis.
Null hypothesis: u = 50
Alternative hypothesis: u < 50
Note that these hypotheses constitute a one-tailed test.
Formulate an analysis plan. For this analysis, the significance level is 0.05. The test method is a one-sample t-test.
Analyze sample data. Using sample data, we compute the standard error (SE), degrees of freedom (DF), and the t statistic test statistic (t).
SE = s / sqrt(n)
S.E = 2.7503
DF = n - 1
D.F = 21
t = (x - u) / SE
t = - 1.054
where s is the standard deviation of the sample, x is the sample mean, u is the hypothesized population mean, and n is the sample size.
The observed sample mean produced a t statistic test statistic of - 1.054.
Thus the P-value in this analysis is 0.153.
Interpret results. Since the P-value (0.153) is greater than the significance level (0.05), we failed to reject the null hypothesis.