GMAT and GPA Scores for 12 MBA Students

Compute the covariance and the determination and interpret your findings.

GMAT- 599 689 584 631 594 643
MBA GPA- 9.6 8.8 7.4 10.0 7.8 9.2
GMAT- 656 594 710 611 593 683
MBA GPA- 9.6 8.4 11.2 7.6 8.8 8.0

A random sample of 10 miniature Tootsie Rolls was taken from a bag. Each piece was weighed on a very accurate scale. The results in grams were

3.087 3.131 3.241 3.241 3.270 3.353 3.400 3.411 3.437 3.477

Click here for the Excel Data File

(a)
Construct a 90% confidence interval for the true mean weight. (Round your answers to 4 decimal places.)

The 90% confidence interval is from to .

(b)
What sample size would be necessary to estimate the true weight with an error of ± 0.03 grams with 90% confidence? (Enter your answer as a whole number (no decimals). Use a z-value taken to three decimal places in your calculations.)

The right size for a sample for 90% confidence is .