One of the important features of a camera is the battery life as measured by the number of shots taken until the battery needs to be recharged. The data shown in the table below contain the battery life of 10 subcompact and 10 compact cameras. Complete parts (a) through (c). 


a. Assuming that the population variances from both types of digital cameras are equal, is there evidence of a difference in the mean battery life between the two types of cameras? Use
α=0.02.
Do not reject or Reject H0. There is _____
▼sufficient, insufficient, evidence
that the means differ.
b. Determine the pvalue in (a) and interpret its meaning.
pvalue= _____
(Round to two decimal places as needed.)
Interpret the pvalue. Choose the correct answer below.
A.The probability of obtaining a sample that yields a t test statistic farther away from 0 in either direction than the computed test statistic if there is no difference in the mean battery life between the two types of digital cameras.
B.The probability of obtaining a sample that yields a t test statistic farther away from 0 in the positive direction than the computed test statistic if there is no difference in the mean battery life between the two types of digital cameras.
C.The probability of obtaining a sample that yields a t test statistic farther away from 0 in the negative direction than the computed test statistic if there is no difference in the mean battery life between the two types of digital cameras.
c. What is meant by a “.05” level of significance ?
A.we have a 5% chance of not rejecting the null hypothesis when the null is false
B.we have a 5% chance of rejecting the null hypothesis when the null hypothesis is true
C.the lowest level of significance for which we do not reject the null is 5%
D. The probability of a Type II error is 5%
a)
Subcompact  Compact  
sample mean x =  41.30  48.30  
standard deviation s=  10.80  13.21  
sample size n=  10  10  
Pooled Variance Sp^{2}=((n_{1}1)s^{2}_{1}+(n_{2}1)*s^{2}_{2})/(n_{1}+n_{2}2)=  145.567 
Point estimate : x1x2=  7.0000  
std. error se =S_{p}*√(1/n1+1/n2)=  5.3957  
test stat t =(x1x2Δo)/Se=  1.2970  
p value : =  0.2110  from excel: tdist(1.297,18,2) 
Do not reject Ho ; There is insufficient evidence that the means differ.
b)
p value =0.21
A.The probability of obtaining a sample that yields a t test statistic farther away from 0 in either direction than the computed test statistic if there is no difference in the mean battery life between the two types of digital cameras.
c)
B.we have a 5% chance of rejecting the null hypothesis when the null hypothesis is true
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