Question

A researcher wishes to see if the average weights of newborn male infants are different from newborn female infants. A random sample of 10 males had a mean weight of 123 ounces with a standard deviation of 8 ounces. A random sample of 8 females had a mean weight of 116 ounces with a standard deviation of 5 ounces. Test claim at LaTeX: \alphaα=0.05. (assume variances are not equal and let males = 1 and females = 2)

The correct CVs are both positive and negative ______.

Answer 1

                  
DF = (s12/n1 + s22/n2)2 / { [ (s12 / n1)2 / (n1 - 1) ] + [ (s22 / n2)2 / (n2 - 1) ] }                  
[ (s12 / n1)2 / (n1 - 1) ] = 4.551      
[ (s22 / n2)2 / (n2 - 1) ] = 1.40      
(s12/n1 + s22/n2)2 = 90.73      
DF =    15.591   

Based on the information provided, the significance level is \alpha = 0.05α=0.05, and the degrees of freedom are df = 15.591In fact, the degrees of freedom are computed as follows, assuming that the population variances are unequal:

Hence, it is found that the critical value for this two-tailed test is t_c = 2.124 for α=0.05 and df = 15.591