uestion 27 What is meant by a precise confidence interval? O The difference between the lower and upper confidence limits is small. O It does not include the population parameter. O It includes the population parameter. O The difference between the lower and upper confidence limits is large. Question 28 1 pt How does a affect statistical power when testing a null hypothesis about u? Oo has no effect on power. O The greater the a, the lesser the power, O The greater the a, the greater the power. O The greater the o, the lesser the power when the population distribution is symmetric, but the greater the d, the greater the power when the population distribution is markedly skewed.