Grade, Learning and Religious Belief

In a Stat 200 survey in Spring 2016, students were asked to rate on a scale of 0 to 10 how much they care about their grades versus how much they care about learning (0 = only care about grades, 10 = only care about learning). A professor has a hypothesis that students who are non-religious (agnostics and atheists) tend to be more curious about knowledge and care less about grades. Let's analyze the survey data and see if the hypothesis is true.

The Stat 200 survey data can be downloaded here and then load to R using the command

survey <- read.csv("stat200_2016spring_survey02.csv")

The variable in each column is described on this webpage.

Student's religious belief is encoded in column named "religion". Lump the "Atheist" and "Agnostic" groups as "non-religious". Create a new column in the data frame survey named 'y' that encodes the non-religious information as follows: set survey$y to 1 if survey$religion is 'Atheist' or 'Agnostic', and set survey$y to 0 if survey$religion is not 'Atheist' and not 'Agnostic'.

a. How many students are non-religious in the survey data?

Number of students who are non-religious = number of y=1 in the data =

b. Perform a two-sample t-test to see if the mean of 'gradeVsLearning' for the y=0 and y=1 groups are significantly different. Remember that the null hypothesis is that there is no difference between the two groups. The alternative hypothesis (the professor's hypothesis) is that non-religious students care more about learning. So the t-test should be one-sided. Enter the group means and p-values to 3 significant figures.
(Hint: You have to specify the alternative parameter in the t.test() function. You have to think about whether to set it to "less" or "more". Also, don't forget to set the parameter var.equal=TRUE.)

Mean of 'gradeVsLearning' for religious (y=0) students =

Mean of 'gradeVsLearning' for non-religious (y=1) students =

P-value of the one-sided t-test:

Is the difference significant at the 5% level?
yes
no

The rest of questions will show up after you finish part (b).