Worksheetsch 15 Random Variables
Total questions: 8
Worksheet time: 11mins
Name
Class
Date
1.
Which of the following random variables is NOT continuous?
a)
Amount of gasoline in a car.
b)
Time it takes to commute to work.
c)
Number of goals scored by a hockey team.
d)
Lifetime of a AAA battery.
2.
A random variable X has a mean of 5 and a st. dev of 0.40. A random variable Y has a mean of 8 and a st. dev of 0.60. If both are independent, what is the mean of X + Y?
a)
13
b)
6.5
c)
14
d)
Not here.
3.
A random variable X has a mean of 5 and a st. dev of 0.40. A random variable Y has a mean of 8 and a st. dev of 0.60. If both are independent, what is the st. dev of X - Y?
a)
0.52
b)
0.72
c)
1.0
d)
Not here
4.
What is the expected number of orders per week?
a)
44.50 orders
b)
45.23 orders
c)
44.61 orders
d)
Not here
5.
A marketing survey compiled data on the number of cars in households. If X = the number of cars
What is the probability that a randomly chosen household has at least two cars?
a)
0.20
b)
0.29
c)
0.39
d)
0.61
6.
The weight of written reports produced in a certain department has a Normal distribution with mean 60 g and standard deviation 12 g. The probability that the next report will weigh less than 45 g is
a)
.1056
b)
.3944
c)
.1042
d)
.8944
7.
State whether it is Discrete or Continuous;
The speed of a car
a)
Discrete
b)
Continuous
8.
State whether it is Discrete or Continuous;
The sum rolled on a pair of dice
a)
Discrete
b)
Continuous
100 %
