Question

in a normal distribution the mean is 65, and the standard deviation is 13 the 30th percentile score is?

Answer 1

@jim_thompson5910 can u please help???

Answer 2

Are you able to use a calculator? Or do you have to use a table?

Answer 3

anything!

Answer 4

alright great, I'm assuming you have a calculator correct?

Answer 5

oh help me with this one: 100 students wrote a test out of 50 marks. the results were normally distributed with a mean of 28 , and standard deviation of 11

Answer 6

oh wait, is this a new problem?

Answer 7

yea and how many students scored between 39 and 50

Answer 8

so you didn't need help with the first?

Answer 9

please i need an answer quick

Answer 10

no i already got the first

Answer 11

oh ok

Answer 12

Use a calculator (preferably a TI 83 or TI 84) and type in

normalcdf(39,50,28,11)

to get

0.135905


So roughly 13.5905% of the distribution scored between 39 and 50


So 0.135905 * 100 = 13.5905 = 13 students scored between 39 and 50

Answer 13

oh kay how abt this one: 8 percent of mabel muffin makers sold are returned because of mushy mess. if the mean number sold is 784 and less than 50 are returned. whts the standared deviation

Answer 14

?

Answer 15

hmm not sure, still working out possible answers, one sec

Answer 16

does it give you a graph at all? that might help if there is one

Answer 17

no

Answer 18

hmm I'm not sure then

Answer 19

it seems like it's missing a critical piece of info, but I can't put my finger on it

Answer 20

thye results of a test are distributed with a mean of 61.5 , and a standard deviation of 10 . to the naerest tenth 35.2% of tjhe test scores are greater than what mark

Answer 21

wht abt the one i just send u

Answer 22

type

invNorm(1- 0.352,61.5,10)

to get

65.2993


So the answer is 65.3

Answer 23

thankyou so much!!!!

Answer 24

you're welcome