We have two samples: Sample 1: the number of observations is 30, standard deviat

ID: 3170728 • Letter: W

Question

We have two samples:

Sample 1: the number of observations is 30, standard deviation is 12, and sample average is 180.

Sample 2: the number of observations is 30, standard deviation is 9, the sample average is 185.

Please assume that the two populations have equal but unknown variances.

Which of the following null hypotheses will be rejected in a 95% confidence test?

Question 4 options:

the two population means are equal

mean two is greater than or equal to mean one

mean one is greater than or equal to mean two

none of the above

the two population means are equal

mean two is greater than or equal to mean one

mean one is greater than or equal to mean two

none of the above

hence pooled std deviation sp=((s12/n1+s22/n2)2/((s12/n1)2/(n1-1) + (s22/n2)2/(n2-1) )1/2=10.607

hence std error =sp(1/n1+1/n2)1/2=2.7386

hence test stat =(x1-x2)/std error =-1.8257

for (n1+n2-2=58) degree of freedom and at above test stat, pvalue =0.074

hence we can not reject null hypothesis.

the two population means are equal

S1 12.000 S2 9.000 n1 30 n2 30 X1 180.000 X2 185.000

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