The lengths of pregnancies have a mean of 268 days and a standard deviation of 15 days. A researcher is concerned that women have taken a particular drug in the past might have shorter lengths of...

The lengths of pregnancies have a mean of 268 days and a standard deviation of 15 days. A researcher is concerned that women have taken a particular drug in the past might have shorter lengths of pregnancies. The researcher sampled n=25 women who had taken the drug and recently given birth, and found they had an average length of pregnancy of 262.9 days. Do these data support the researcher's claim? (use standard diviation of 0.01, one tail test)

Calculate the effect size using cohen's d.