I tried to do this question but could not. I used descriptive statistics, the fu
ID: 3260058 • Letter: I
Question
I tried to do this question but could not. I used descriptive statistics, the function in excel, to get the numbers I did above. However I think I am wrong and it would be great if I could get some help!
Thank you.
2. In many species, males are more likely to attract females if the males have high testosterone levels. Are males with high testosterone paying a cost for this extra mating success in other ways? One hypothesis is that males with high testosterone might be less able to fight off disease; that is, their high levels of testosterone might reduce their immunocompetence. To test this idea Hasselquist et.al. (1999) experimentally increased the testosterone level of 13 male red wing blackbirds by surgically implanting a small permeable tube filled with testosterone They measured immunocompetence as the rate of antibody production in response to a nonpathogenic antigen in each bird's blood serum both before and after the implant. The antibody production rates were measured optically, in units of log 10 optical density per minute. Before implant 4.65 3.91 4.91 4.50 4.80 4.88 4.88 4.78 4.98 4.87 4.75 4.70 4.93 After implant 4.44 4.30 4.98 4.45 5.00 5.00 5.01 4.96 5.02 4.73 4.77 4.60 5.01 Male number 3 4 6 7 8 9 10 12 13Explanation / Answer
we will use paired t-test
as samples are same before and after ,
now below are results
p-value = P(t < -1.2714) = 0.1138
note that 2 will not be multiplied as it is one-directional , we want to see the mean has increased or not
since
0.1138 > 0.05 {signifiance level}
we fail to reject the null hypothesis
and conclude that there is not sufficient evidence that mean has increased .
t-Test: Paired Two Sample for Means before After Mean 4.733846154 4.79 Variance 0.078308974 0.068433333 Observations 13 13 Pearson Correlation 0.829066656 Hypothesized Mean Difference 0 df 12 t Stat -1.271409177 P(T<=t) one-tail 0.113836936 t Critical one-tail 1.782287556 P(T<=t) two-tail 0.227673873 t Critical two-tail 2.17881283