A teacher wants to find out the average number of weekly reading hours of her students. She noted the number of reading hours of
2 answers:
You might be interested in
suppose the people have weights that are normally distributed with a mean of 177 lb and a standard deviation of 26 lb.
Find the probability that if a person is randomly selected, his weight will be greater than 174 pounds?
Assume that weights of people are normally distributed with a mean of 177 lb and a standard deviation of 26 lb.
Mean = 177
standard deviation = 26
We find z-score using given mean and standard deviation
z =
=
=-0.11538
Probability (z>-0.11538) = 1 - 0.4562 (use normal distribution table)
= 0.5438
P(weight will be greater than 174 lb) = 0.5438
Answer:
P = 0.008908
Step-by-step explanation:
The complete question is:
The table below describes the smoking habits of a group of asthma sufferers
Nonsmokers Light Smoker Heavy smoker Total
Men 303 35 37 375
Women 413 31 45 489
Total 716 66 82 864
If two different people are randomly selected from the 864 subjects, find the probability that they are both heavy smokers.
The number of ways in which we can select x subjects from a group of n subject is given by the combination and it is calculated as:
Now, there are 82C2 ways to select subjects that are both heavy smokers. Because we are going to select 2 subjects from a group of 82 heavy smokers. So, it is calculated as:
At the same way, there are 864C2 ways to select 2 different people from the 864 subjects. It is equal to:
Then, the probability P that two different people from the 864 subjects are both heavy smokers is: