Homework SourseWhich of the following statements are correct I The t distri
Which of the following statements are correct?
I. The t distribution has more area in its tails than the z distribution for all n
II. When constructing a 2-sample t interval for the difference of means the conservative method of choosing degrees of freedom will result in a wider confidence interval than other methods.
III. You would always use a z procedure rather than a t procedure if you have a sample size greater than 30.
An experiment was conducted to compare the efficacies of two drugs in the prevention of tapeworms in the stomachs of a new breed of sheep. Samples of size 5 and 8 from each breed were given the drug and the two sample means were 28.6 and 40.0 worms/sheep. The variances in the two groups are 198 and 232, respectively, and that the number of worms in the stomachs has an approximate normal distribution. A 95% confidence interval for the the difference in the mean number of worms per sheep is:
| 1. | Which of the following statements are correct? I. The t distribution has more area in its tails than the z distribution for all n II. When constructing a 2-sample t interval for the difference of means the conservative method of choosing degrees of freedom will result in a wider confidence interval than other methods. III. You would always use a z procedure rather than a t procedure if you have a sample size greater than 30. | ||||||||||||||||
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Solution
1.
I and III only
2.
-11.4
