The following data represents the age (in weeks) at which babies first crawl based on a survey of 12 months. The data are normally distributed and s=10.765 weeks. Construct and interpret a 90% confidence interval for the poplulation standard diviation of the age (in weeks) at which babies crawl.

Data- 53 31 45 37 37 25

48 37 59 26 38 28

Select a,b, or c and fill in the blank.

a) There is a 90% probability that the true population standard deviation is between _____ and ______.

b) If repeated samples are taken, 90% of them will have the sample standard deviation between ______ and _______.

c) There is 90% confidence that the population standard deviation is bewteen ____ and ______.