1. Looking at a bag with four different colored marbles, there is a 25% chance t
ID: 2927528 • Letter: 1
Question
1. Looking at a bag with four different colored marbles, there is a 25% chance that a marble you take out will be red and a 50% chance that a marble you take out will be green. What is the probability that you will select a red or green marble?
a. 0.25
b. 0.75
c. 0.125
d. none
2. A researcher looks at depressive symptoms in a group of people before and after exposure to internet cat videos. The obtained results are as follows: t(20) = 10.80, p < 0.01. What kind of t-test is this and how many people were in the study?
a. cannot be determined
b. one-sample;21 persons
c. paired-samples t-test; 21persons
d. independent t-test; 22 persons
A researcher conducts a hypothesis test to evaluate the effect of a treatment. The hypothesis test produces a z-score of z = 0.80. Assuming that the researcher is using a two tailed test, what decision should be made?
a. the researcher should fail to reject the null hypothesis with a=0.05.
b. cannot be determined
c. the researcher should reject the null hypothesis with a=0.05.
the researcher shuold accept the null hypothesis with a=0.05.
A researcher obtains t = 2.05 for a repeated-measures study using a sample of n = 50. Based on this t value, what is the correct decision for a two-tailed test?
a. cannot be determined
b. reject the null hypothesis with a=0.05 but not with a=0.01.
c. reject the null hypothesis with either a=0.05 or a=0.01.
d fail to reject the null hypothesis with either a=0.05 or a=0.01.
Explanation / Answer
Ans:
1)P(red or green)=0.25+0.50=0.75
2)Option C is correct
paired-samples t-test; 21persons
3)p-value(two tailed)=0.4237
As,p-value>0.05,we fail to reject null hypothesis.
Option a is correct.
4)df=50-1=49
t=2.05
p-value( two tailed)=TDIST(2.05,49,2)=0.0457
For alpha=0.05
As,p-value=0.0457<0.05,we reject null hypothesis.
But for alpha=0.01
As,p-value=0.0457>0.01,we fail to reject null hypothesis.
Option b is correct.
( reject the null hypothesis with a=0.05 but not with a=0.01)
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