Population Proportions

Front

Is it plausible that 57% of all students at Ahmad's university would agree that a third party is needed, given the confidence interval (0.599, 0.781)?

Back

No, 57% is not in the interval of plausible values.

Front

Is it plausible that 57% of students at Ahmad's sister Diedra's school would agree that a third party is needed, given the 95% confidence interval (0.557, 0.743)?

Back

Yes, 57% is in the interval of plausible values for the population proportion.

Front

A video game gives players a reward of gold coins after they defeat an enemy. The creators of the game want players to have a chance at earning bonus coins when they defeat a certain challenging enemy. The creators attempt to program the game so that the bonus is awarded randomly with a 30% probability after the enemy is defeated. To see if the bonus is being awarded as intended, the creators defeated the enemy in a series of 100 attempts (they're willing to treat this as a random sample). After each attempt, they recorded whether or not the bonus was awarded. They used the results to build a 95% confidence interval for p, the proportion of attempts that will be rewarded with the bonus. The resulting interval was (0.323, 0.517).

Back

The bonus most likely isn't being awarded at the intended rate of 30%.

Front

What does the confidence interval 0.12±0.06 suggest about the rare item being awarded at the intended rate of 15%?

Back

It's plausible that the rare item is being awarded at the intended rate of 15%.

Front

A market analyst wants to construct a 90% confidence interval for the proportion of Los Angeles residents with a landline telephone based on a survey of 200 residents, where 96 have a landline. What is the confidence interval?

Back

0.48±0.058

Front

Back

Front

What is the smallest sample size required for a 95% confidence level with a margin of error of 2 percentage points, assuming p-hat=0.90?

Back

865

Front

A survey of 400 randomly selected homes from a large city with over 30,000 homes showed that 16 of the sampled homes didn't have a television. Based on this sample, what is the 95% confidence interval for the proportion of homes in this city that don't have a television?

Back