In a 2003 survey of 670 college students, 164 said they used illegal drugs. In a more recent survey of 1045 college students, 204 said they used illegal drugs. Use a 0.01 significance level to test the claim that the proportion of college students using illegal drugs has decreased since 2003. QUESTI…

Statistics
Find a value c such that

P(-c < Z < c) = 0.6

where Z has a standard normal distribution.

You may use either the Z table or R to find the necessary percentile. Example: To find the 10th percentile for a standard normal distribution in R qnorm(0.1)

The q in the function if for quantile. A quantile is basically the same thing as a percentile except that we use area instead of percent. So the 10th percentile is equal to the 0.1 quantile. You don’t need it for this question, but to find the 10th percentile for a normal distribution with any mean and standard deviation the R command is qnorm(0.1,m,s)

#WHERE m=MEAN AND s=STANDARD DEVIATION

Statistics
Find a value c such that

P(-c < Z < c) = 0.6

where Z has a standard normal distribution.

You may use either the Z table or R to find the necessary percentile. Example: To find the 10th percentile for a standard normal distribution in R qnorm(0.1)

The q in the function if for quantile. A quantile is basically the same thing as a percentile except that we use area instead of percent. So the 10th percentile is equal to the 0.1 quantile. You don’t need it for this question, but to find the 10th percentile for a normal distribution with any mean and standard deviation the R command is qnorm(0.1,m,s)

#WHERE m=MEAN AND s=STANDARD DEVIATION