Question

Brad is testing whether school is more enjoyable when students are making high grades. He asked 110 students if they enjoyed school and whether their GPA was above or below 3.5. He found that 38 of the 45 students with a GPA above 3.5 reported that they enjoyed school, and 7 of the 65 students with a GPA below 3.5 reported that they enjoyed school. What is the probability that a student with a GPA below 3.5 does not enjoy school?

Answer 1

If 7/65 enjoyed school, how many do not enjoy it? (Of students below 3.5 gpa)

Answer 2

so i divide those together cause i need a percentage

Answer 3

And then once you find that number which should be pretty simple, divide it by the total number of students below 3.5

Answer 4

\[\large\rm Probability = \frac{Student ~with~below~ 3.5GPA ~who~ doesnt~ enjoy~ school}{Total ~students ~with~ GPA ~below ~3.5} \]

Answer 5

so it like 89 percentage

Answer 6

That's correct

Answer 7

thank you i was thinking about that but im making sure

Answer 8

An easy check is to see if the percentage you got makes sense. Maybe you decided to do 65/58 for whatever reason. That percentage is 112%. Does it make sense? Of course not, so try again until an answer looks right

Answer 9

so the 89 percent is wrong

Answer 10

No no I was just giving an example of a wrong answer and why it's wrong

Answer 11

can u help me with one more please

Answer 12

The grades on the last math exam had a mean of 72%. Assume the population of grades on math exams is known to be distributed normally, with a standard deviation of 5%. Approximately what percent of students earn a score between 72% and 87%?

Answer 13

Sure

Answer 14

i dont get that question

The grades on the last math exam had a mean of 72%. Assume the population of grades on math exams is known to be distributed normally, with a standard deviation of 5%. Approximately what percent of students earn a score between 72% and 87%?

Answer 15

Hmm maybe I'm also rusty in this but wouldn't it be 49.7%? If the deviation after applying the normal distribution doesn't extend past the upper boundary and the lower boundary is the mean itself, that would mean an equal number of students will be below 72% as there will be above it. And since normal distribution says that 99.7% will be within three standard deviations (which is +/-15%), only .3% of the students above 72% will also be above 87%. That means the 50% below 72% is automatically cut out, and the .3% that was too high is also cut out. 100%-50%-.3%=49.7%

Answer 16

the option are 49.9%
1%
50%
47.7%

Answer 17

Okay yeah I might have messed up with the .3%, it could be .15% if you cut it in half. So that would round up to 49.9%

Answer 18

Sorry like I said very rusty, math is not my thing

Answer 19

thank youuuuuuuuuuuuu :) lolll me to so it okay

Answer 20

Did the explanation make sense? I made the assumption that you knew how normal distributions work without explaining much

Answer 21

yeah but i kept gettin mix up with the percentage the same way u didnt round i didnt either so that mess me up also i