A researcher is interested in estimating the mean BMI of adults in UAE . He selected a random sample of 20 adults which yielded a mean of 24.5 kg/m2 and a standard deviation of 1.3 kg/m2. He believes that the distribution of BMI is strongly skewed. Which distribution should he use to construct the confidence interval? a. Neither t nor standard normal distribution.

b. t distribution with 19 degrees of freedom

c. t distribution with 20 degrees of freedom

d. Standard normal distribution