Question

Facebook recently examined all active Facebook users and determined that the average user has 183 Facebook friends. Suppose that the population of number of Facebook friends of a randomly selected user has a standard deviation of σ = 241. Facebook draws a SRS of 250 Facebook users. What is the probability that the average number of Facebook friends is less than 175? Apply the Central Limit Theorem.

Caution: do not round at your intermediate steps. Hint: you may need to use Excel for this calculation.

Group of answer choices

0.2998

0.5000

0.6873

0.9235

0.3714

Answer 1

n = sample size ( SRS of size ) = 250

We hae to find the probability that the average number of Facebook friends is less than 175

We use formula of Z score and find Z score for 175

We have to find the left side area of the Z because we have given word " less than "

Select empty box from excel and type

=NORMSDIST(-0.524859363)

Excel always given you less than type probability

=NORMSDIST(-0.524859363)

While using excel do not forget to type = sign

Press "enter" key

We get probability as 0.29984048

Round probability up to 4 decimal

So we get probability as 0.2998

Final answer :-

First choice is correct choice

Probability that the average number of Facebook friends is less than 175 = 0.2998