Question

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Answer 1

familiar with calculating zscores ?

Answer 2

I know about the chart but never understood how to find numbers from it.:/

Answer 3

good, its just a chart -
lets find the zscores for the given observations first

Answer 4

whats the zscore of 1,965 ?

Answer 5

Hm, that number isn't even in my zscore...?

Answer 6

Yeag 1965 is the observation, use below formula to find the zscore :

\(\large \text{zscore} = \dfrac{\text{observation - mean}}{\text{standard deviation}}\)

Answer 7

zscore for 1965 = \(\dfrac{1965 - 2100}{40} = ?\)

Answer 8

Ah okay, So the z-score is -3.375?

Answer 9

Yep ! find the corresponding probability in your table

Answer 10

I can't find it; which line?

Answer 11

http://www.stat.ufl.edu/~athienit/Tables/Ztable.pdf

Answer 12

-3.375 ~ -3.38

Answer 13

look up in second row

Answer 14

is it next to the side of -3.4?

Answer 15

its below that row

Answer 16

put your one finger on -3.3 ROW
and put the next finger on 0.08 COLUMN

Answer 17

Oh, .004! Just a question, how does that give 0.9480?

Answer 18

Correct ! so the probability for the observation 1965 or less is 0.004

Answer 19

next, find the zscore for second observation : 2165

Answer 20

That would be .9996?

Answer 21

whats the zscore ?

Answer 22

Oh, I thought that was the zscore.:/ Sorry, not good w. these; Is this one is the first box or below it?

Answer 23

In the 2.1 column?

Answer 24

again, you need to find the zscore for the observation 2165 first

Answer 25

zscore for 2165 = (2165 - 2100)/40
= ?

Answer 26

sorry, 1.625. The z-score is next to 1.6?