According to Pew Research Center, 71% of Internet users accessed video-sharing sites last month. A random sample of 50 Internet users was selected. Using the normal approximation to the binomial distribution, what is the probability that fewer than 40 people from this sample access video-sharing sites

The probability that fewer than 40 people from this sample access video-sharing sites is P=0.92.

Step-by-step explanation:

We have a populations proportion of internet users accessing video-sharing sites of p=0.71. We take a sample of n=50. This can be treated as a binomial random variable, but a normal distribution approximation is prefered, as the sample size is big to make all the calculations for the binomial distribution.

To approximate the binomial distribution to a normal distribution, we calculate the parameters as:

To calculate the probability that fewer that 40 people from this sample access video-sharing sites, we apply the continuity factor:

let x be the money she spent so that she can earn the free t-shirt.

since, she already spent $112.49

⇒

also, as per the statement: jennifer must spend $250 or more in order to qualify for a free t-shirt at the store.

then,

we have an inequality i.,e

subtract 112.49 from both sides we get;

therefore, $137. 51 more money does jennifer need to spend so that she can earn the free t-shirt

it would take 7/10 of an hour too fill the pool.

step-by-step explanation: