# Statistics

posted by .

I have a couple questions I answer for home work could some look atthem and tell me If I am doing them right I also am having problems understanding the variance and standard deviation are the site you can suggest that would help with this I need a step by step help

11. For the following scores, find the (a) mean,
Usually the best measure of central tendency is the ordinary average, the sum of all
the scores divided by the number of scores. In statistics, this is called the mean. The
average, or mean, of a group of scores is a representative value.
2+ 2 +0 + 5 + 1+ 4+ 1+ 3+ 0+ 0+ 1+ 4+ 4+ 0+ 1+ 4+ 3+ 4+ 2+ 1+ 0= 42
42/21=2

(b) median, Another alternative to the mean is the median. If you line up all the scores from
lowest to highest, the middle score is the median.

0 ,0,0,0,0, 1,1,1,1,1,2,2,2,3,3,4,4,4,4,4,5
Median 2

(c) sum of squared deviations,
0x0=0, 1x1=1, 2x2=4,3x3=9, 4x4=16, 5x5=25
0+0+0+0+0+1+1+1+1+1+4+4+4+9+9+16+16+16+16+16+25= 140

(d) variance

(e) standard deviation:

14.

On a standard measure of hearing ability, the mean is 300 and the standard deviation
is 20. Give the Z scores for persons who score
(a) 340

z=(340-300)/(20)

z=(40)/(20)

z=2

(b) 310

z=(310-300)/(20)

z=(10)/(20)

z=(1)/(2)

(c)260.

z=(260-300)/(20)

z=(-40)/(20)

z=-(40)/(20)

z=-2

Give the raw scores for persons whose Z scores on this test are
(d) 2.4

2.4*20+300=x

x=2.4*20+300

x=48+300

x=348

(e)1.5

1.5*20+300=x

x=1.5*20+300

x=30+300

x=330

(f) 0

0*20+300=x

x=0*20+300

x=0+300

x=300

(g) -4.5.

-4.5*20+300=x

x=-4.5*20+300

x=-90+300

x=210

any help would be appreciated
Thank you

• Statistics -

the variance is the sum of the squares of the deviations from the mean.
Since most of you data values hover around 0-5, it is hard to tell whether you squared the differences or the actual data values.
I see a 5x5, so it appears that you simply squared the data values.

take each data value, subtract it from the mean, then square it.
now add these up, they should all be positive, and divide by 21

the standard deviation is the square root of that variance.

I don't know at what level of sophistication your study of statistic is, but there is a difference in how the variance and standard deviations are calculated.
If you "google" variation and standard deviation, most pages will explain that difference
Here is a page that gives a short explanation

http://www.chem.utoronto.ca/coursenotes/analsci/StatsTutorial/MeasMeanVar.html

Your last question shows up as imcomplete.
A Z score is found by:

so suppose one of your values is 350, then the z-score for that data value would be (350 - 300)/20 or 2.5

• Statistics -

For the following scores, find the (a) mean, (b) median, (c) sum of squared deviations, (d) variance, and (e) standard deviation:
3.0, 3.4, 2.6, 3.3, 3.5, 3.2

• Statistics -

A psychologist interested in political behavior measured the square footage of the desks in the official office of four U.S. governors and of four chief executive officers (CEOs) of major U.S. corporations. The figures for the governors were 44, 36, 52, and 40 square feet. The figures for the CEOs were 32, 60, 48, and 36 square feet. (a) Figure the means and standard deviations for the governors and for the CEOs. (b) Explain, to a person who has never had a course in statistics, what you have done. (c) Note the ways in which the means and standard deviations differ, and speculate on the possible meaning of these differences, presuming that they are representative of U.S. governors and large corporationsâ€™ CEOs in general.

## Similar Questions

1. ### statistics

Would someone mind checking me and pointing out which may be incorrect. I THINK I get it but.... Calculate the range, variance, standard deviation for the data set given 72, 80, 80, 82, 88, 90, 96?
2. ### Please tell me if i did this correct

Given the following frequency distribution, find the mean, variance, and standard deviation. Please show all of your work. Errors Frequency 51-53 9 54-56 19 57-59 16 60-62 24 63-65 25 This is what I got: Mean = 59.19 Variance = 1.43 …
3. ### college math

20. Calculate the range, variance, and standard deviation of the following data set: 5, 5, 6, 6, 6, 8, 8, 8, 8, 10, 10, 11, 12, 12, 20 (Points: 5) Range = 15; Variance = 225; Standard Deviation = 7.5 Range = 3.85; Variance = 14; Standard …
4. ### Math Statistics

In general, what is the relationship between the standard deviation and variance?
5. ### math

Using the data in the table, calculate the mean, range, variance, and standard deviation, and then answer questions e and f. Round the variance and standard deviation to one decimal place. a. Mean b. Range c. Variance d. Standard deviation …
6. ### math

Using the data in the table, calculate the mean, range, variance, and standard deviation, and then answer questions e and f. Round the variance and standard deviation to one decimal place. a. Mean b. Range c. Variance d. Standard deviation …
7. ### Statistics

The table below shows the LOS for a sample of 11 discharged patients. Using the data in the table, calculate the mean, range, variance, and standard deviation, and then answer questions e and f. Round the variance and standard deviation …
8. ### math

Using the data in the table, calculate the mean, range, variance, and standard deviation, and then answer questions e and f. Round the variance and standard deviation to one decimal place. a. Mean b. Range c. Variance d. Standard deviation …
9. ### Statistics

The table below shows the LOS for a sample of 11 discharged patients. Using the data in the table, calculate the mean, range, variance, and standard deviation, and then answer questions e and f. Round the variance and standard deviation …
10. ### Statistics (Math 210)

Hi there, I am doing my statistics homework and am having trouble with a few problems. I sincerely appreciate any help I receive! :) A manufacturer claims the standard deviation of salt in their meat is .5. An SRS of 18 samples shows …

More Similar Questions