Community X lives in an area where there are poor healthy food options. A random

Question

Community X lives in an area where there are poor healthy food options. A random sample of 64 individuals from Community X were tested for their total serum cholesterol levels. The mean total serum cholesterol level for this sample was 194.5 (SD=20). The population total serum cholesterol mean is 190. Using this information, answer the questions below.

What are the critical values for a z test with an a=.05?

a.       For a one-sided test

b.      Write out the alternative hypothesis for the one-sided test

c.       For a two-sided test

d.      Write out the alternative hypothesis for the two-sided test

Using a z test, calculate the z value for the difference in mean serum cholesterol levels between the sample and population

Is the sample mean total serum cholesterol level statistically greater than the population mean at an a=.05? Explain how you came to this conclusion

Explanation / Answer

a)t .05 critical value of z test is 1.64 (from table)

b) ha: mu_a > mu_0

c)t .05 critical value of z test is 1.96 (from table)

d) Ha mu_a not equal to mu_o

e)

z = (mua-mu_0)/ (SD/sqrt(N))

= 194.4 -190/ 20/ sqrt(64) = 4.5/ 1.25 =3.6

as 3.6 isgreater tha z critical 1.64 we can reject the null and say yes the sample has greater cholesterol.

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