The authors of a paper studied a random sample of 355 Twitter users. For each Twitter user in the sample, the "tweets" sent during a particular time period were analyzed and the Twitter user was classified into one of the following categories based on the type of messages they usually sent.
Category | Description |
---|---|
IS | Information sharing |
OC | Opinions and complaints |
RT | Random thoughts |
ME | Me now (what I am doing now) |
O | Other |
The accompanying table gives the observed counts for the five categories (approximate values read from a graph in the paper).
Twitter Type | IS | OC | RT | ME | O |
---|---|---|---|---|---|
Observed count | 53 | 59 | 66 | 103 | 74 |
Carry out a hypothesis test to determine if there is convincing
evidence that the proportions of Twitter users falling into each of
the five categories are not all the same. Use a significance level
of 0.05.
Let p1, p2,
p3, p4, and
p5 be the proportions of the five message types
among the population of Twitter users.
State the null and alternative hypotheses.
H0: p1 =
p2 = p3 =
p4 = p5 = 0.5
Ha: H0 is not
true.
H0: p1 =
p2 = p3 =
p4 = p5 = 355
Ha: H0 is not
true.
H0: p1 =
p2 = p3 =
p4 = p5 = 70
Ha: H0 is not
true.
H0: p1 =
p2 = p3 =
p4 = p5 = 0.2
Ha: H0 is not
true.
H0: p1 =
p2 = p3 =
p4 = p5 = 0.05
Ha: H0 is not
true.
Calculate the test statistic. (Round your answer to two decimal
places.)
χ2 =
What is the P-value for the test? (Round your answer to
four decimal places.)
P-value =
What can you conclude?
Do not reject H0. There is not enough evidence to conclude that the proportions of Twitter users falling into the five categories are not all the same.
Do not reject H0. There is convincing evidence to conclude that the proportions of Twitter users falling into the five categories are not all the same.
Reject H0. There is convincing evidence to conclude that the proportions of Twitter users falling into the five categories are not all the same.
Reject H0. There is not enough evidence to conclude that the proportions of Twitter users falling into the five categories are not all the same.
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