Question

Jump to level 1 The mean voltage and standard deviation of 14 batteries from each manufacturer were measured. The results are summarized in the following table. Manufacturer Sample mean voltage (millivolts) Sample standard deviatio A 173 4 B 170 2 What type of hypothesis test should be performed? Select What is the test statistic? Ex: 0.123 What is the number of degrees of freedom? Ex: 250 Does sufficient evidence exist to support the claim that the voltage of the batteries made by the two manufacturers is different at the a = 0.1 significance level? Select 2 Check Try again Feedback 2

Answer 1

Answer Date: 31/07/2020 To test the hypothesis is that the voltage of batteries made by the two manufacturers is different at 10% significance level. The type of unpaired t test is performed due to each sample is taken from different populations. The null and alternative hypothesis is, H:/4 = 42 H2:4,7 42

The t-test statistics is, t= (11 - #2)-(4-u) sĩ să + n2 (173-170)-0 42 22 + V14 14 = 2.510 The t-test statistics is 2.510 The degrees of freedom are, (s? /n, + s} /n) d.f.= (silm)/(m, -1)+(sz /n)/(n2 - 1) (42/14+ 22/14) (42/14)/(14 – 1) + (22/14)/(14 - 1) = = 19.12 = 19

The degrees of freedom are 19 The t-critical value is, The sample size is small and two-tailed test. Look in the column headed a = 0.10 and the row headed in the t distribution table by using degree of freedom is and the t-critical value is -1.729 and 1.729. Decision The t-test statistics which is 2.510 is higher than t-critical value which is 1.729, so the null hypothesis is rejected at 10% level of significance. It does sufficient evidence exist to support the claim indicate that the voltage of batteries made by the two manufacturers is different. The result is statistically significant.