Question 726754
The sample size is 300. The number of successes are 225, so the sample proportion is 


phat = x/n = 225/300 = 0.75


So the sample proportion is phat = <font color="red">0.75</font>


Notes:


1) phat (pronounced pee-hat) is the sample proportion that estimates the population proportion p. This is NOT the same as the p-value. The symbol you'll most likely see for phat is <img src="http://latex.codecogs.com/gif.latex?\LARGE \hat{p}" title="\LARGE \hat{p}" /> (basically a p with a ^ directly over it)


2) x = number of successes and n = sample size


3) A "success" in this case is finding a battery that lasts 30 hours or more. If you find a battery that lasts less than 30 hours, then it's not a success and it's a failure.


4) The sample proportion (phat) is equal to the ratio or fraction of the number of successes (x) over the number in the sample (n)