@rational Betty's Bite-Size Candies are packaged in bags. The number of candies per bag is normally distributed, with a mean of 50 and a standard deviation of 3. At a checkpoint, a sample of bags is checked, and 4 bags contain fewer than 47. How many bags were probably taken as samples?

Question

bloomlocke367 · Answer

What do I do here?

bloomlocke367 · Answer

@rational

rational · Answer

http://upload.wikimedia.org/wikipedia/commons/thumb/8/8c/Standard_deviation_diagram.svg/2000px-Standard_deviation_diagram.svg.png

rational · Answer

We have standard deviation, $\sigma = 3$
Notice that 47 is 1 $\sigma $ less than the mean, 50.

rational · Answer

so the probability for one bag to have less than 47 candies would be :  13.6+2.1+0.1 = 15.8 %

bloomlocke367 · Answer

okay..... I'm still confused, sorry

rational · Answer

15.8%  = 4

can you guess what 100% would be ?

rational · Answer

its okay, you will understand these after doing 2-3 prblems

rational · Answer

0.158x = 4

solve x

bloomlocke367 · Answer

I got 25.316... I did a proportion:$$\frac{ 15.8 }{ 4 }=\frac{ 100 }{ ? }$$

rational · Answer

yes so approximately 25 bags are taken as sample

bloomlocke367 · Answer

oh, wow. okay

rational · Answer

dont watch it, its very advanced video

rational · Answer

il delete it

bloomlocke367 · Answer

okay...