Two species of rat were grown under controlled conditions for 16 days and the following weight...

Two species of rat were grown under controlled conditions for 16 days and the following weight gains (in grams) were obtained. If the number is negative, it means the rat lost weight. (calculate everything for this problem - do not use built in excel formulas)
Species A -23 4 0 -18 7 32 -4 -2 Species B 21 38 20 24 24 58 16 -16 14 28 -5 25

a) Calculate a 95% confidence interval for each species mean b) Calculate a 95% confidence interval for the difference of the means between each species c) Test the hypothesis that species A has gained no weight. d) Test the hypothesis that the means are equal for both species. (Solve it, do not use Excel formulas) e) Based on your results, describe the differences between the following methods for comparing the samples, and assess whether each is an effective method. Be specific in terms of what each method tells you about these two samples (not just what the results are, but what the method is actually examining to get those results). In other words, which methods, if any, can be misleading, and why? 1) Looking for overlap between the mean ± 1 standard deviation 2) Looking for overlap between (mean ± SE) 3) Looking for overlap between (mean ± 2SE) 4) Looking for overlap between the ranges 5) Seeing if the 95% confidence interval of the difference of the means includes 0.

Expert Solution

Note - A to D has been solved in detailed. allowed to answer only 4 questions in one post.

a) Calculate a 95% confidence interval for each species mean

Species A - 95% CI

Species B - 95% CI

b) Calculate a 95% confidence interval for the difference of the means between each species

c) Test the hypothesis that species A has gained no weight.

d) Test the hypothesis that the means are equal for both species

Conclusion: the mean of the two samples is not equal but are different.

orchestra answered 2 years ago

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