Thread: statistics-deviation

so on this long hw we got theere was like 50 questiosn and there are a few t/f things i'm not sure about:
3. a sampling distributoin is the distribution of a sample (i think false?)
4. the standard deviation of a sample is smaller than the standard deviation of the parent distribution. in fact the sample standard deviation equals the population standard deviation divided by the square root of sample size (true?)
5. the size of standard deviation is directly related to the size of hte data set; the larger the data set, the larger the standard deviation (false ?)
17. as the sample size increases, the shape of ht distribution of sample data gets more normal (true?)
these here i just dont have an idea
14. the smaller the sample, the smaller(shorter) the shape
28. the smaller the sample, the less skewed the sample will be even though the parent ( population) distribution is very skewed.
30. the larger the sample size, the closer the shape of the sampling distribution gets to the shape of hte parent distribution
42. changes in shape of spread do not affect the heigth of hte distribution. all distributions have the same height
43. values in random sample uniformly imitate the values of the parent distribution; for example you will get a sample of 2,4,6 and 8 from 1,2,3,4,5,6,7,8,9

THANKS SO MUCH in advance

Originally Posted by hongster5

3. a sampling distributoin is the distribution of a sample (i think false?)

False the sampling distribution is the distribution of some statistic computed
from the data values in a sample, under repeated sampling

4. the standard deviation of a sample is smaller than the standard deviation of the parent distribution. in fact the sample standard deviation equals the population standard deviation divided by the square root of sample size (true?)

False, it is the standard deviation (standard error) of sample means that
this is true of.

5. the size of standard deviation is directly related to the size of hte data set; the larger the data set, the larger the standard deviation (false ?)

False

17. as the sample size increases, the shape of ht distribution of sample data gets more normal (true?)

False, the distribution of the sample data gets more like that of the
distribution being sampled from. It is the distribution of sample means that this is true of.

RonL

Originally Posted by hongster5

14. the smaller the sample, the smaller(shorter) the shape

Obscure wording, don't think I even know what this is asking

28. the smaller the sample, the less skewed the sample will be even though the parent ( population) distribution is very skewed.

Its certainly true for sample sizes of 1 and 2.

30. the larger the sample size, the closer the shape of the sampling distribution gets to the shape of hte parent distribution

With appropriate meaning for the terms closer and shape, this is true

42. changes in shape of spread do not affect the heigth of hte distribution. all distributions have the same height

The area under a density is always 1, so if the spread increases the height
decreases.

43. values in random sample uniformly imitate the values of the parent distribution; for example you will get a sample of 2,4,6 and 8 from 1,2,3,4,5,6,7,8,9

Once again I don't even know what this question is asking.

RonL

thanks alot! yea i know these wordings are really confusing