power module biostats error in calculating power exercise

[apeterson91]

There is an error when calculating the z score associated with the 95th percentile of the normal distribution.

it keeps asking for input of qnorm(0.95) which I give, but it then repeats the message prompting for the qnorm input

[WilCrofter]

Adam,

We believe you are on question 22 of Bootcamp's 3rd module. If so, the hint is misleading. It prompts you to type qnorm(0.95 but it tests for zAlpha <- qnorm(0.95). From our run this morning:

Since our significance level is 0.05, ...blah, blah... Use this function now on the value 0.95 and assign the result to a new variable called 'zAlpha'.

ANSWER: zAlpha <- qnorm(0.95) Great job!

Here's a way to work around problems of this sort. If you hit the escape key while running swirl, swirl will exit and save your progress, but the course material will remain available in a data frame named mod. You can view it by typing View(mod) at the R prompt. Questions are in mod's Output column, expected answers in its 'Correct.Answer` column. So, for instance,

> mod[22, "Correct.Answer"] [1] "zAlpha <- qnorm(0.95)"

Now you can run swirl again, tell it you want to resume where you left off, and give the answer it's testing for.

We used R's grep function to find the correct line number:

> grep(".95",mod[,"Output"]) [1] 22

Cheers, Bill & Gina

[apeterson91]

That did it!

I don't know if you've gotten enough thanks and praise already, but this is a seriously cool program. I'm using it alongside coursera's biostat class, and it's phenomenal. I'm in a Master's Informatics program and they don't teach us nearly enough of this stuff.

Also- Happy Thanksgiving!

-Adam Peterson B.S. Biochemistry MSHI/MHA Candidate Department of Health Management and Informatics

On Nov 28, 2013, at 8:44 AM, William R Bauer notifications@github.com wrote:

Adam,

We believe you are on question 22 of Bootcamp's 3rd module. If so, the hint is misleading. It prompts you to type qnorm(0.95 but it tests for zAlpha <- qnorm(0.95). From our run this morning:

Since our significance level is 0.05, ...blah, blah... Use this function now on the value 0.95 and assign the result to a new variable called 'zAlpha'.

ANSWER: zAlpha <- qnorm(0.95) Great job!

Here's a way to work around problems of this sort. If you hit the escape key while running swirl, swirl will exit and save your progress, but the course material will remain available in a data frame named mod. You can view it by typing View(mod) at the R prompt. Questions are in mod's Output column, expected answers in its 'Correct.Answer` column. So, for instance,

mod[22, "Correct.Answer"] [1] "zAlpha <- qnorm(0.95)"

Now you can run swirl again, tell it you want to resume where you left off, and give the answer it's testing for.

We used R's grep function to find the correct line number:

grep(".95",mod[,"Output"]) [1] 22

Cheers, Bill & Gina

— Reply to this email directly or view it on GitHub.

[WilCrofter]

Thanks, Adam. Glad it worked, and Happy Thanksgiving to you as well!

Nick Carchedi, the talent behind most of swirl, deserves the lion's share of credit. We agree that both swirl and coursera are very cool projects. We're a (mostly) retired compsci couple lending a bit of development help on the next version of swirl.

We'll close this issue. If you have any more trouble just open another and we'll do our best.