A sample of 20 students who had recently taken elementary st

A sample of 20 students who had recently taken elementary statistics yielded the following information on brand of calculator owned. (T = Texas Instruments, H = Hewlett Packard, C = Casio, S = Sharp):

(a) Estimate the true proportion of all such students who own a Texas Instruments calculator.


(b) Of the 5 students who owned a TI calculator, 2 had graphing calculators. Estimate the proportion of students who do not own a TI graphing calculator.

Solution

A) THERE ARE IN ALL 5 STUDENTS WHO OWN A TEXAS INSTRUMENT

SO THE TRUE PROPORTION WILL BE 5/20 = 1/4

B) 5 STUDENTS OWN A TI AND 2 HAD GRAPHIC CALCULATORS, SO ONLY 3 DOES NOT HAVE THE GRAPHIC CALCULATOR

SO THE PROPORTION WILL BE 3/20