Math  /  Data & Statistics

QuestionDoes the average Presbyterian donate more than the average Catholic in church on Sundays? The 58 randomly observed members of the Presbyterian church donated an average of $27\$ 27 with a standard deviation of \13.The55randomlyobservedmembersoftheCatholicchurchdonatedanaverageof$26withastandarddeviationof13. The 55 randomly observed members of the Catholic church donated an average of \$26 with a standard deviation of \7 7. What can be concluded at the α=0.10\alpha=0.10 level of significance? a. For this study, we should use Select an answer b. The null and alternative hypotheses would be: H0H_{0} : Select an answer Select an answer Select an answer (2) (please enter a decimal) H1H_{1} : Select an answer Select an answer Select an answer (Please enter a decimal) c. The test statistic ? : = \square (please show your answer to 3 decimal places.) d. The pp-value == \square (Please show your answer to 4 decimal places.) e. The pp-value is ? α\alpha f. Based on this, we should Select an answer the null hypothesis. g. Thus, the final conclusion is that ... The results are statistically significant at α=0.10\alpha=0.10, so there is sufficient evidence to conclude that the mean donation for the 58 Presbyterians that were observed is more than the mean donation for the 55 Catholics that were observed. The results are statistically significant at α=0.10\alpha=0.10, so there is sufficient evidence to conclude that the population mean amount of money that Presbyterians donate is more than the population mean amount of money that Catholics donate. The results are statistically insignificant at α=0.10\alpha=0.10, so there is insufficient evidence to conclude that the population mean amount of money that Presbyterians donate is more than the population mean amount of money that Catholics donate. The results are statistically insignificant at α=0.10\alpha=0.10, so there is statistically significant evidence to conclude that the population mean amount of money that Presbyterians donate is equal to the population mean amount of money that Catholics donate.

Studdy Solution

STEP 1

What is this asking? We want to find out if Presbyterians donate more money on average than Catholics, based on samples from both groups. Watch out! Don't mix up the sample data with the population parameters.
We're using the samples to *infer* something about the populations!

STEP 2

1. Set up the hypothesis test
2. Calculate the test statistic
3. Find the p-value
4. Make a decision

STEP 3

Our **null hypothesis** (H0H_0) is that there's *no difference* in average donations between the two groups.
Mathematically, this means: H0:μPμC0H_0: \mu_P - \mu_C \le 0 where μP\mu_P is the population mean donation of Presbyterians and μC\mu_C is the population mean donation of Catholics.
In other words, the difference is less than or equal to zero.

STEP 4

Our **alternative hypothesis** (H1H_1) is what we're trying to find evidence *for*.
In this case, it's that Presbyterians donate *more* on average: H1:μPμC>0H_1: \mu_P - \mu_C > 0 Meaning the difference is greater than zero.
This is a *right-tailed test*!

STEP 5

The significance level, α\alpha, is **0.10**.
This is our cutoff for deciding if the results are statistically significant.

STEP 6

Since we have two independent samples and we're comparing means, we'll use a **two-sample t-test**.

STEP 7

The formula for the **two-sample t-test** is: t=(xˉPxˉC)(μPμC)sP2nP+sC2nCt = \frac{(\bar{x}_P - \bar{x}_C) - (\mu_P - \mu_C)}{\sqrt{\frac{s_P^2}{n_P} + \frac{s_C^2}{n_C}}} Here, xˉP=$27\bar{x}_P = \$27 and xˉC=$26\bar{x}_C = \$26 are the **sample means**, sP=$13s_P = \$13 and sC=$7s_C = \$7 are the **sample standard deviations**, and nP=58n_P = 58 and nC=55n_C = 55 are the **sample sizes**.
Under the null hypothesis, (μPμC)=0(\mu_P - \mu_C) = 0.
Plugging in the values: t=($27$26)0($13)258+($7)255=$1$16958+$4955=$1$2.914+$0.891$1$3.805$1$1.9510.513t = \frac{(\$27 - \$26) - 0}{\sqrt{\frac{(\$13)^2}{58} + \frac{(\$7)^2}{55}}} = \frac{\$1}{\sqrt{\frac{\$169}{58} + \frac{\$49}{55}}} = \frac{\$1}{\sqrt{\$2.914 + \$0.891}} \approx \frac{\$1}{\sqrt{\$3.805}} \approx \frac{\$1}{\$1.951} \approx 0.513 So, our **test statistic** is approximately **0.513**.

STEP 8

The **p-value** is the probability of observing a test statistic as extreme as, or more extreme than, the one we calculated, *assuming the null hypothesis is true*.

STEP 9

Since this is a right-tailed test, we want the probability of getting a t-value greater than or equal to **0.513**.
Using a t-distribution calculator or table with the appropriate degrees of freedom (which can be approximated), we find the p-value is approximately **0.3050**.

STEP 10

Our **p-value (0.3050)** is *greater* than our **significance level (0.10)**.

STEP 11

Since the p-value is greater than alpha, we **fail to reject the null hypothesis**.

STEP 12

a. Two-Sample t-test b. H0:μPμC0H_0: \mu_P - \mu_C \le 0, H1:μPμC>0H_1: \mu_P - \mu_C > 0 c. t0.513t \approx 0.513 d. p0.3050p \approx 0.3050 e. p>αp > \alpha f. Fail to reject g. The results are statistically insignificant at α=0.10\alpha = 0.10, so there is insufficient evidence to conclude that the population mean amount of money that Presbyterians donate is more than the population mean amount of money that Catholics donate.

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