Question

An article reports that in a sample of 355 calves less than 4 days old, 104 had lesions on their bronchial lymph nodes, while in a sample of 467 calves more than 4 days old, 147 had such lesions. Can you conclude that the proportion of calves with lesions differs between the two age groups? Find the P-value and state a conclusion. Round the answer to four decimal places. The P-value is conclude that the proportion of calves with lesions differs between the two age We cannot groups.

Answer 1

Sample 1 Sample number of events Sample size 104 Given 355 Given ! Sample proportion 凸 0.293 Sample 2 Sample number of events Sample size x= 147 Given 467 Given 2 Sample proportion 0.3148 712 n1P1+n2P2 = 0.3054 Pooled proportion n + n2 Null hypothesis Alternative hypothesis Level of significance α=0.05 say Right tailed Critical value 1.65 From z table Rejection region :Z> 1.65 Standard error i 12 Point estimate 0.0218 Test statistic: 0.67 1 72 p-value For z- -0.67, the right tailed p-value is 0.7486 Decision: Do not Reject H0 because p-value> a Conclusion We cannot conclude that the proportion of calves with lesions differes