Question

Statistics
The diameters of grapefruits in a certain orchard are normally distributed with a mean of 7.30 inches and a standard deviation of 0.80 inches. Show all work.

(A) What percentage of the grapefruits in this orchard have diameters less than 6.7 inches?

(B) What percentage of the grapefruits in this orchard are larger than 7.20 inches?

What I have wrote out
mean=m=7.30
Standard deviation=s=0.80
(A) what % have diameters less than 6.7

(B) what %are larger than 7.20

Answer 1

A is asking: P(X<6.7)

Answer 2

B is asking P(X>7.2)

Answer 3

z = (6.7 - mean)/sd

Answer 4

6.7-7.30/0.80

Answer 5

good, thats our z score for A

Answer 6

we get a negative and we know that it wants the value of everything to the left of it

Answer 7

.5 - zvalue

Answer 8

zvalue will probably be called a Pvalue later in the book

Answer 9

-0.75

Answer 10

yep

Answer 11

Can we use the bell curve ?

Answer 12

we are .

Answer 13

yes, mathtalk that is what they are all made of (im in statistics-the book says elementary statistics- my first class of it0

Answer 14

somebody show how to proceed here

Answer 15

please

Answer 16

so 0.5000-0.2734(from the table)=

Answer 17

its alot to wrap up form previous posts ... but in a nutshell, you get a zscore and look that up in a table to get a value

Answer 18

then work it into the question to find an answer

Answer 19

.2734 is good, so that should do it for A

Answer 20

B is trickier in that it wants values all to the right of z

Answer 21

same concept, but we have to adjust our thinking a little to accomodate for it

Answer 22

don't we do 0.5000-0.2734?

Answer 23

yes

Answer 24

A is the result of .5 - .2734

Answer 25

for the first one? right.

Answer 26

yep

Answer 27

oh ok, then i have 0.2266

Answer 28

good

Answer 29

so then I write it like this right?
P(x<6.7)=0.23

Answer 30

B needs some care taken to it.