A study is conducted to compare the tensile strength of two

A study is conducted to compare the tensile strength of two types of roof coatings. It is thought that, on the average, butyl coating s are stronger than acrylic coatings. The following data are obtained: Butyl Acrylic 16 nA 16 300.22 319.11 sa 1298.47 si 472.71 Assume independent samples and both samples are from normally distributed populations Use a 0.05 (a) hat are the hypotheses? (b) Calculate the test statistic: (c) What is the P value of the test? If needed, the Smith-Satterthwaite procedure results in y df 17. d) what is your decision about the null hypothesis

Solution

H0: Means are equal

Ha: Means are not equal

Two tailed test for comparison of two sample means.

P value and statistical significance:
  The two-tailed P value equals 0.9892
  By conventional criteria, this difference is considered to be not statistically significant.

Confidence interval:
  The mean of Group One minus Group Two equals 18.8900
  95% confidence interval of this difference: From -2803.2023 to 2840.9823

Intermediate values used in calculations:
  t = 0.0137
  df = 30
  standard error of difference = 1381.839

(Unpaired)

As p value is higher than alpha, accept null hypothesis.