Question

Which of the following is always true of a normal distribution?

I. It extends exactly three standard deviations in each direction from the mean
II. The mean equals the median, which equals the mode.
III. An interval one standard deviation wide centered at the mean has more area under the curve than an interval one standard deviation wide centered at a value to the right of the mean

A. I only
B. II and III only
C. I and III only
D. II only
E. I, II, III

Answer 1

if you get me the ans. from ans.book, i may be able to tell u

Answer 2

@perl i think its E. I, II, and III but I wasn't sure about A because it says exactly, can you check my answer please?

Answer 3

statement ii is correct
if median = mean then according to relation 3median= 2mean +mode ,
mode is also equal

Answer 4

i dont know about iii & i--statements
but i think statement -i is not true
because ther is only one standard deviation for mean.
i have not studied 3standard dev. for 1mean.
this suggests that 3 std. dev. may not be true for normal distribution

Answer 5

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Answer 6

man

Answer 7

wth

Answer 8

wht is this bruh

Answer 9

i hav called all the available... so that you can get the help.... you must be waiting for a long time....

Answer 10

why dont u help @lall

Answer 11

because i dont know

Answer 12

i hav seen the man was waiting for a long time

Answer 13

if nobody answers then u should not waste your time on os
find other ways to get the sol.

Answer 14

ohhh @lall it fine i get ti

Answer 15

ok
the normal distribution curve is symmetrical so there are equal numbers of samples above and below the mean
FIRST - what does that tell you about the mean and the median??

The mean is the centre and highest frequency distribution
SECOND - What does that ell you about the mean and the mode?

when you have answered those two points you will know whether ii is correct.

just LOOK at the graph of the curve. IF you take a band centred at the mean and a band the SAME widthe centred somewhere else - is it possible for the second bamd to have MORE area under it????

Answer that and you will know if iii is true

Now look at the curve again - does it STOP at 3SD? or is it possible to have sample points MORE than 3SD from the mean (See if the curve actually touches the x axis ANYWHERE)
When oyu have answered that oyu will know if I is true

All these points can be established by a review of the curve shape and the meaning of the 3 basic 'centre' points which are the basis of oyur study of statisitcs