Since your sample size is small, you can use a one-sample t-test formula.
With your data:
z = (2.8 - 3)/(0.3/√10)
Finish the calculation.
Next, check a t-table using 9 degrees of freedom (which is n - 1) for a one-tailed test at .05 level of significance. Compare your z-statistic above to the critical value in the table to determine the outcome.
A group of 10 students have average of GPA of 2.8 with SD of 0.3. Does this group present enough evidence to indicate that the average GPA is less than 3.0? Make your decision at a 5% level of significance
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Substitute t for z in my statements. Sorry for any confusion.
4 answers