MATH 1342 Practice T2

Find P( Z < -0.92) means to find the area below (or to the left) of z=-0.92 and round to four decimals.

(a)  

Find the z-score to two decimals with 0.9234 area to the right.  

(a)  

If A and B are independent events with P(A)=0.3 and P(B)=0.6, find P(A AND B) to two decimals.

(a)  

If the probability of a student taking a math class is 0.40, the probability of taking a physics class is 0.30, and the probability of taking a math class and a physics class is 0.02, what is the probability of a student taking a math class or a physics class to two decimals?

(a)  

The mean number of minutes for app engagement by a tablet user is 8.2 minutes. Suppose the distribution is approximately normal and the standard deviation is one minute. Find the 3rd Quartile to two decimals. 

(a)  

The mean number of minutes for app engagement by a tablet user is 8.2 minutes. Suppose the standard deviation is one minute. Suppose a random sample of 60 users were taken. What is the probability that the sample mean is less than 8.25 minutes (for the sample of 60)? Use Desmos and round to four decimals.

(a)  

The mean number of minutes for app engagement by a tablet user is 8.2 minutes. Suppose the distribution is approximately normal and the standard deviation is one minute.  Find the probability that a user of the app is engaged for between 8 and 8.5 minutes. Round to four decimal places. 

(a)  

The final exam scores in a history class were normally distributed with a mean of 63 and a standard deviation of 5. Find the 90th percentile. That is, find the exam score such that 90% of all the scores fall below.  Use Desmos & round to one decimal.

(a)  

The final exam scores in a history class were normally distributed with a mean of 63 and a standard deviation of 5. Find the probability that a randomly selected student scored less than 85, that is find P(X< 85). Use Desmos & round to four decimals. 

(a)  

Assume that the national average score on a standardized test is 1010, and the standard deviation is 200, where scores are normally distributed. Find the score that s the 95th percentile. Round to the nearest whole number.

(a)