In: Statistics and Probability
A researcher claims that the number of homicide
crimes by season is uniformly distributed. To test this claim, you
randomly select
1 comma 1921,192 homicides from a recent year and record the season when each happened. The table shows the results. Atalphaα =0.100.10, test the researcher's claim. |
Season |
Frequency, f |
||
---|---|---|---|---|
Spring |
301301 |
|||
Summer |
315315 |
|||
Fall |
296296 |
|||
Winter |
280280 |
State
Upper H 0H0
and
Upper H Subscript aHa
and identify the claim.
Upper H 0H0:
The distribution of the number of homicide crimes by season
is uniformly distributed.
Upper H Subscript aHa:
The distribution of the number of homicide crimes by season
is not uniformly distributed.
Which hypothesis is the claim?
Upper H 0H0
Your answer is correct.
Upper H Subscript aHa
Calculate the test statistic.
Ho:The distribution of the number of homicide crimes by season is uniformly distributed.
Ha: The distribution of the number of homicide crimes by season is not uniformly distributed.
Ho is the claim:
Applying chi square goodness of fit test:
relative | observed | Expected | residual | Chi square | |
category | frequency | Oi | Ei=total*p | R2i=(Oi-Ei)/√Ei | R2i=(Oi-Ei)2/Ei |
Spring | 0.250 | 301 | 298.00 | 0.17 | 0.030 |
summer | 0.250 | 315 | 298.00 | 0.98 | 0.970 |
Fall | 0.250 | 296 | 298.00 | -0.12 | 0.013 |
Winter | 0.250 | 280 | 298.00 | -1.04 | 1.087 |
total | 1.000 | 1192 | 1192 | 2.101 |
test statistic =2.101
(crtical value =6.251 ; p value =0.5518 ; fail to reject Ho)