Normal distribution was invented by ________.

(a)

Laplace

(b)

De-Moivre

(c)

Gauss

(d)

all the above

If Z is a standard normal variate, the proportion of items lying between Z = –0.5 and Z = –3.0 is ________.

(a)

0.4987

(b)

0.1915

(c)

0.3072

(d)

0.3098

The parameters of the normal distribution \(f(x)=\left(\frac{1}{\sqrt{72 \pi}}\right)\)\(\frac{e^{-(x-10)^{2}}}{72}\) –∞ <  x  <  ∞ ________.

(a)

(10,6)

(b)

(10,36)

(c)

(6,10)

(d)

(36,10)

An experiment succeeds twice as often as it fails. The chance that in the next six trials, there shall be at least four successes is ________.

(a)

240/729

(b)

489/729

(c)

496/729

(d)

251/729

The average percentage of failure in a certain examination is 40. The probability that out of a group of 6 candidates atleast 4 passed in the examination are ________.

(a)

0.5443

(b)

0.4543

(c)

0.5543

(d)

0.4573

Which of the following statements is/are true regarding the normal distribution curve?

(a)

it is symmetrical and bell shaped curve

(b)

it is asymptotic in that each end approaches the horizontal axis but never reaches it

(c)

its mean, median and mode are located at the same point

(d)

all of the above statements are true.

Cape town is estimated to have 21% of homes whose owners subscribe to the satelite service, DSTV. If a random sample of your home in taken, what is the probability that all four home subscribe to DSTV?

(a)

0.2100

(b)

0.5000

(c)

0.8791

(d)

0.0019

The area under the standard normal curve between Z=-∞ and z=∞ is

(a)

0

(b)

0.5

(c)

1

(d)

0.75

In 8 throws of a die, 1 or 3 is considered a success. Then the mean number of successes is ___________

(a)

\(\frac{8}{3}\)

(b)

\(\frac{4}{3}\)

(c)

\(\frac{2}{3}\)

(d)

\(\frac{5}{3}\)

For a normal distribution if the mean is m, mode is n and median is m, then ___________

(a)

m > m₁ > m₀

(b)

m < m₁ < m₀

(c)

m ≠ m₁ x m₀

(d)

m = m₁ = m₀