If the alternative hypothesis of a test is H
a:
, what is the corresponding null hypothesis?
a.H
a:
b.H
a:
c.H
a:
d.Ha:
Q. 2If a test of H
0:
versus H
a:
were conducted for a sample of size 20, what would be the critical region for a significance level of
?
a.t > 2.09
b.t < -2.09 or t > 2.09
c.t < -1.73 or t > 1.73
d.(-4.5,4.5)
Q. 3 Suppose the
p-value equals 0.018 for testing whether or not bags of candy had on average more than 25 pieces of candy in them. Which of the following conclusions would be correct for testing the hypotheses H
0:
versus H
a:
?
a.It can be concluded that there are more than 25 pieces of candy on average in a bag at the
level.
b.It can be concluded that there are more than 25 pieces of candy on average in a bag at the
level.
c.It can be concluded that there are more than 25 pieces of candy on average in a bag at the
level, and at the
level.
d.It can be concluded that there are not more than 25 pieces of candy on average in a bag at the level.
Q. 4 Suppose a random sample of 15 individual's ages had the following statistics:
, s = 4.1. What is the test statistic for testing H
0:
versus H
a:
?
a.
t = -1.89,
df = 15
b.
t = 30.23,
df = 29
c.
z = -1.89
d.
t = 1.89,
df = 14
Q. 5A random sample of 25 packets of flower seeds had a mean of 32 seeds. How many degrees of freedom would the
t statistic for this study have?
a.25
b.31
c.24
d.It depends on the sample variance.
Q. 6
Which of the following t distribution most closely resembles the standard normal distribution?
a.A
t distribution with
df = 0.
b.A
t distribution with
df = 50.
c.A
t distribution with
df = 200.
d.A
t distribution with
df = 1.
Q. 7
When should a t statistic be used?
a.When the mean
is known but the standard deviation
is unknown and must be estimated by
s.
b.When both the mean is unknown and must be estimated by
and the standard deviation
is unknown and must be estimated by
s.
c.When both the mean
is known and the standard deviation
is known.
d.When the standard deviation is known but the mean is unknown and must be estimated by .
Q. 8 Suppose a random sample of 10 televisions has a mean life of 25 years. If it is known that
, what is the test statistic for testing H
0:
and H
a:
?
a.There is not enough information given to determine the test statistic.
b.-2.66
c.0.60
d.0.004