(Solved): Six different national brands of chocolate chip cookies were randomly selected at the supermarket. T ...

Six different national brands of chocolate chip cookies were randomly selected at the supermarket. The grams of fat per serving are as follows: 8; 8; 10; 6; 9; 9. Assume the underlying distribution is approximately normal.

NOTE: If you are using a Student's t-distribution, you may assume that the underlying population is normally distributed. (In general, you must first prove that assumption, though.)

IOTE: If you are using a Student's t-distribution, you may assume that the underlying population is normally distributed. (In general, you must first prove that assumption, though.) \( \square \) Part (a) Construct a \( 90 \% \) confidence interval for the population mean grams of fat per serving of chocolate chip cookies sold in supermarkets. (i) State the confidence interval. (Round your answers to two decimal places.) (ii) Sratrh tha oranh (iii) Calculate the error bound. (Round your answer to two decimal places.) [ ] \( \boxminus \) Part (b) If you wanted a smaller error bound while keeping the same level of confidence, what should have been changed in the study before it was done? increase the sample size decrease the sample size determine the population standard deviation nothing can be changed to guarantee a smaller error bound