Question

Statistics

Question 1

Why should you always divide by degrees of freedom when calculating
the sample variance?

a. Because the formula for population variance systematically
underestimates the population variance when it is used on only a
sample of scores.

b. Because the formula for population variance is the best match a
sample of scores.

c. Because the formula for population variance systematically
overestimates the population variance when it used on only a sample
of scores.

d. None of the above. You should never divide by degrees of freedom
when computing sample variance.

QUESTION 2

Under what circumstances must you use the computational formula for SS?

a. Never. The computational formula will always give the same
result as the definitional formula.

b. Never. There is only one formula for SS - the definitional
formula.

c. Whenever the mean is a whole number.

d. Whenever the mean is a decimal and rounding error would occur
when summing the squared deviations in the definitional
formula.

Answer #1

If you want examples please comment.

When using inferential statistics, it is critical to
have:
More than one degree of freedom.
A truly random sample of the population.
A binomial random variable
A strong correlation with a Poisson distribution.
A normally distributed population.
The three ways of assessing probabilities
are:
Classical, Empirical, and Subjective
Normal, Poisson, and Hypergeometric
Type I, Type II, and Secular
Binomial, Geometric, and a priori
Global test, Histogram, and Stepwise
If there are three, equally-likely events, the
probability of each event occurring...

1. The F ratio may be used to assess difference between
(among):
a. two sample means b. three sample means c. four sample means
d. All of these
3. With a two-group experimental design, the independent
variable has been manipulated at:
a. one level b. two levels c. three levels d. all of these
4. For the F ratio, if alpha is set at .05, it remains at .05 of
comparisons are made between (among)
a. 2 group means b....

1 of 2
Geoff is the proud owner of a restaurant. He is interested in
determining whether his Wagyu beef or Hiramasa kingfish sashimi
should be marketed as the Geoff Special. Geoff has selected a
random sample of 20 people to taste his Wagyu beef and give it a
score out of 100. He also selected a different random sample of 20
people to taste his Hiramasa kingfish sashimi and give it a score
out of 100.
The sample mean...

Hypothesis testing is the basis of inferential statistics.
Statisticians are always coming up with new tests and testing new
characteristics of population parameters. One of the simplest tests
that currently exist is the one-sample test for means.
A random sample is drawn. If the population variance is known,
then we use the Z test; if the population variance is unknown, we
use the T test. In addition, there are some additional assumptions
that can be made. For example, if a...

No explanation required;
Question 1
A two-independent-sample t-test is computed when mean
differences are compared between TWO OR MORE groups sampled from a
population with an unknown variance.
Select one:
True
False
Q 2
Question 2
A counselor records the number of disagreements (per
session) among couples during group counseling sessions. If the
number of disagreements is distributed normally with a mean of 4.4
disagreements and a standard deviation of 0.4, then what proportion
of couples disagree at least four...

Assume that you have a sample of n 1 equals n1=9, with the
sample mean Upper X overbar 1 equals X1=50, and a sample standard
deviation of Upper S 1 equals 5 comma S1=5, and you have an
independent sample of n 2 equals n2=17 from another population with
a sample mean of Upper X overbar 2 equals X2=39
and the sample standard deviation Upper S2=6.
Complete parts (a) through (d).
a. What is the value of the pooled-variance tSTAT...

Question 1
The main reason a research uses a t-test instead of a z-test is
when little is known about population (mean and standard
deviation).
1) True
2) False
Question 2
Values in the t‐table are not actually listed by sample
size but by degrees of freedom (df).
1) True
2) False
Question 3
A 90 percent confidence level is equivalent to an alpha level of
0.10
1) True
2) False
Question 4
A professor wants to know if her...

T-tests are used when you want to examine differences but you do
not know everything about the population. There are three types of
t-tests that you may choose to do: one-sample t-test, independent
sample t-test, or dependent sample t-test. You can calculate these
by hand, in SPSS, or in Excel. The instructions below can be used
for SPSS and your textbook offers instructions for using Excel.
Single-sample t-tests
These tests are used when you want to determine the
probability that...

1.The sample mean is an unbiased estimator for
the population mean. This means:
The sample mean always equals the population mean.
The average sample mean, over all possible samples, equals the
population mean.
The sample mean will only vary a little from the population
mean.
The sample mean has a normal distribution.
2.Which of the following statements is
CORRECTabout the sampling distribution of the
sample mean:
The standard error of the sample mean will decrease as the
sample size increases....

The tails of the normal curve never touch the abscissa
because
theoretically, any value is possible.
it is a line plot.
normal data are not continuous.
it is not possible to have a value with 0 relative
frequency
What proportion of values are between 0 and 3 standard
deviations from the mean?
0.5
half of 0.50
half of 0.997
less than 3%
A negative z-score indicates that the original score was
greater than the mean.
equal to the standard deviation....

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