In: Statistics and Probability
A manufacturer of colored candies states that 13% of the candies in a bag should be brown, 14% yellow, 13% red,24% blue20%orange, and 16%
green. A student randomly selected a bag of colored candies. He counted the number of candies of each color and obtained the results shown in the table. Test whether the bag of colored candies follows the distribution stated above at
alpha equalsα=0.05 level of significance. Using the level of significance
alpha equalsα=0.05, test whether the color distribution is the same.Click here to view the table.
Click here to view the table of critical values of the chi-square distribution
Determine the null and alternative hypotheses. Choose the correct answer below.
A.H0:The distribution of colors is at least as uniform as stated by the manufacturer.
H1:The distribution of colors is less uniform than stated by the manufacturer.
B.H0:The distribution of colors is not the same as stated by the manufacturer.
H1:The distribution of colors is the same as stated by the manufacturer.
C.H0:The distribution of colors is the same as stated by the manufacturer.
H1:The distribution of colors is not the same as stated by the manufacturer.
D.H0:The distribution of colors is at most as uniform as stated by the manufacturer.
H1:The distribution of colors is more uniform than stated by the manufacturer.
Compute the expected counts for each color.
Color |
Frequency |
Expected Count |
|
---|---|---|---|
Brown |
6161 |
nothing |
|
Yellow |
6666 |
nothing |
|
Red |
5555 |
nothing |
|
Blue |
6363 |
nothing |
|
Orange |
9393 |
nothing |
|
Green |
6666 |
nothing |
|
(Round to two decimal places as needed.) |
What is the test statistic?
chi Subscript 0 Superscript 2χ20 |
equals= |
nothing |
(Round to three decimal places as needed.) |
What is the range of P-values of the test?
The range of P-values of the test is
▼
between 0.01 and 0.025.
between 0.025 and 0.05.
less than 0.01.
between 0.05 and 0.10.
greater than 0.10.
Based on the results, do the colors follow the same distribution as stated in the problem?
A.Do not reject Upper H 0Do not reject H0.
There insufficient sufficient evidence that the distribution of colors is not the same as stated by the manufacturer.
B. Reject Upper H 0Reject H0. There is sufficient sufficientevidence that the distribution of colors is not the same as stated by the manufacturer.
C. Do not reject Upper H 0Do not reject H0.
There is not sufficient not sufficient evidence that the distribution of colors is not the same as stated by the manufacturer.
D. Reject Upper H 0Reject H0.
There is not sufficientnot sufficient
evidence that the distribution of colors is not the same as stated by the manufacturer.
Solution:-
State the hypotheses. The first step is to state the null hypothesis and an alternative hypothesis.
Null hypothesis: There is sufficient sufficient evidence that the distribution of colors is the same as stated by the manufacturer.
Alternative hypothesis: There is sufficient sufficient evidence that the distribution of colors is not the same as stated by the manufacturer.
Formulate an analysis plan. For this analysis, the significance level is 0.05. Using sample data, we will conduct a chi-square goodness of fit test of the null hypothesis.
Analyze sample data. Applying the chi-square goodness of fit test to sample data, we compute the degrees of freedom, the expected frequency counts, and the chi-square test statistic. Based on the chi-square statistic and the degrees of freedom, we determine the P-value.
DF = k - 1 = 6 - 1
D.F = 5
(Ei) = n * pi
X2 = 16.827
where DF is the degrees of freedom, k is the number of levels of the categorical variable, n is the number of observations in the sample, Ei is the expected frequency count for level i, Oi is the observed frequency count for level i, and X2 is the chi-square test statistic.
The P-value is the probability that a chi-square statistic having 5 degrees of freedom is more extreme than 16.827.
We use the Chi-Square Distribution Calculator to find P(X2 > 16.827) = 0.0048.
The range of P-values of the test is less than 0.01.
Interpret results. Since the P-value (0.0048) is less than the significance level (0.05), we have to reject the null hypothesis.
B) Reject H0. There is sufficient sufficient evidence that the distribution of colors is not the same as stated by the manufacturer.