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WorksheetsProbability Distributions
Total questions: 10
Worksheet time: 50mins
If a normal distribution has a mean of 50 and a standard deviation of 5, what is the probability of selecting a value less than 45?
0.1587
0.5000
0.8413
0.0250
A factory produces light bulbs with a mean lifespan of 800 hours and a standard deviation of 50 hours. What is the probability that a randomly selected bulb lasts more than 850 hours?
0.0250
0.5000
0.8413
0.1587
In a normal distribution, what is the area under the curve to the left of the mean?
0.75
0.25
0.5
1.0
Choose the correct option by reading the statements about Mathematical expectation
(i) E(c)=c is where is a constant (ii) E(c X) = c E(X) where c is a constant
(ⅲ)E(X+Y) =E(X). E(Y) (ⅳ) E(XY)=E(X)+E(Y)
All the four statements are true
Only (iii) and (iv) are true.
Only (i) and (ii) are true.
All the four statements are false.
If a random variable X has the probability density function above,
then the variance of X is closest to:
0.0844
0.0935
0.1426
0.1985
0.4296
If a random variable X is normally distributed with a mean of 10 and a standard deviation of 1.5, then
Pr(8 < X < 11)
is closest to
0.7052
0.2948
0.6285
0.6563
0.3437
It is known that E[X] = 2 for a given random variable X and var(X) = 5. Determine E[X2].
1
3
4
7
9
fX(x)=kx2, 0≤x≤1
Determine the value of k.
1
2
3
4
