4.true
5.false
6.true
7.true
8.true
Answer:
19/21 or .90
Step-by-step explanation:
Common denominator.
Multiply 4/7 by 3 which equals to 12/21
Multiply 1/3 by 7 which equals to 7/21
Add 12/21 and 7/21
Answer: 19/21
Answer: 0.9617
Step-by-step explanation:
Given : The proportion of adults use their phones in meetings or classes : p=0.57
Number of adults randomly selected : n= 9
Let x be the random variable that represents the number of adults use their phones in meetings or classes.
By using binomial probability formula, to find the probability of getting success in x trials.

The probability that at least 3 of them use their smartphones in meetings or classes will be :-

Hence, the required probability is 0.9617 .