Question

(3.13) Use Table A to find the value z of a standard Normal variable that satisfies each of the following conditions. (Use the value of z from Table A that comes closest to satisfying the condition.) In each case, sketch a standard Normal curve with your value of z marked on the axis.


The point z with 20% of the observations falling below it.

A. 0.84
B. -0.84
C. 0.85
D. -0.85

Answer 1

http://ebooks.bfwpub.com/bps6e/frontmatter/bps6e_tables.pdf

Answer 2

since your z table is already setup for "area" to the left of z; you just have to match a field entry closest to .2000

Answer 3

your table appears to be defunct ....

Answer 4

But how are they getting .84 or .85 ?

Answer 5

find 2 field values that are closest to .2000

Answer 6

.2005 > .2000 > .1997

do you agree? which one is it closer to?

Answer 7

.1997

Answer 8

2000+5 > 2000 > 2000-3
1997
since 3 is closer than 5

Answer 9

pfft, helps if a can read tho ... that what 1977?

Answer 10

.00 .01 .02 .03 .04 .05 .06 .07 .08 .09
-----------------------------------------------------------
||
-0.8 || .2119 .2090 .2061 .2033 .2005 .1977 .1949 .1922 .1894 .1867
^^
.2000

Answer 11

the 2005 is closer so use it:

add the row value to the column value

Answer 12

oh! I see now.

Answer 13

yeah, its pretty simple once you understand the formating :)

Answer 14

The point z with 20% of the observations falling above it.

would it be -0.85 for that

Answer 15

falling ABOVE it? or below it?

Answer 16

Well, first question was below it and the second above it.

Answer 17

-0.84 is the closest z value to 20% below

the mirror image nature of the distribution tho would indicate that:

0.84 is the closest z value to 20% above

Answer 18

look at z=0.84; row .8 col .04 and see that it is .2005

Answer 19

well, +.5000

Answer 20

It is.

Answer 21

i still think your table is still defunct ....