In: Statistics and Probability
On average, Americans have lived in 2 places by the time they are 18 years old. Is this average more for college students? The 57 randomly selected college students who answered the survey question had lived in an average of 2.17 places by the time they were 18 years old. The standard deviation for the survey group was 0.8. What can be concluded at the αα = 0.10 level of significance?
H0: ? p μ ? = ≠ < > _________
H1: ? p μ ? < = ≠ > _________
Solution:-
a) We should use t-test for a population mean.
b)
State the hypotheses. The first step is to state the null hypothesis and an alternative hypothesis.
Null hypothesis: u = 2.0
Alternative hypothesis: u > 2.0
Note that these hypotheses constitute a one-tailed test. The null hypothesis will be rejected if the sample mean is too small.
Formulate an analysis plan. For this analysis, the significance level is 0.10. 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 = 0.10596
DF = n - 1
D.F = 56
a)
t = (x - u) / SE
t = 1.60
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 1.60.
b) P-value = P(t > 1.60)
Use t-value calculator to find p-value
P-value = 0.058
c) Interpret results. Since the P-value (0.058) is less than the significance level (0.10), we have to reject the null hypothesis.
d) Based on this, we should fail to reject reject null hypothesis.
e)
Thus, the final conclusion is that The data suggest that the populaton mean is significantly more than 2 at αα = 0.10, so there is statistically significant evidence to conclude that the population mean number of places that college students lived in by the time they were 18 years old is more than 2.
f) If the population mean number of places that college students lived in by the time they were 18 years old is 2 and if you survey another 57 college students then there would be a 5.71323686% chance that the sample mean for these 57 college students would be greater than 2.17.
g)
If the population mean number of places that college students lived in by the time they were 18 years old is 2 and if you survey another 57 college students, then there would be a 10% chance that we would end up falsely concuding that the population mean number of places that college students lived in by the time they were 18 years old is more than 2.