Which of the following is not a measure of dispersion?

(a)

Range

(b)

Standard deviation

(c)

Arithmetic mean

(d)

Variance

The range of the data 8, 8, 8, 8, 8. . . 8 is

(a)

0

(b)

1

(c)

8

(d)

3

The mean of 100 observations is 40 and their standard deviation is 3. The sum of squares of all observations is

(a)

40000

(b)

160900

(c)

160000

(d)

30000

The probability a red marble selected at random from a jar containing p red, q blue and r green marbles is

(a)

\(\frac { q }{ p+q+r } \)

(b)

\(\frac { p }{ p+q+r } \)

(c)

\(\frac { p+q }{ p+q+r } \)

(d)

\(\frac { p+r }{ p+q+r } \)

A page is selected at random from a book. The probability that the digit at units place of the page number chosen is less than 7 is

(a)

\(\frac{3}{10}\)

(b)

\(\frac{7}{10}\)

(c)

\(\frac{3}{9}\)

(d)

\(\frac{7}{9}\)

The probability of getting a job for a person is \(\frac{x}{3}\). If the probability of not getting the job is \(\frac{2}{3}\)  then the value of x is

(a)

2

(b)

1

(c)

3

(d)

1.5

The number of televisions sold in each day of a week are 13, 8, 4, 9, 7, 12, 10. Find its standard deviation.

The amount of rainfall in a particular season for 6 days are given as 17.8 cm, 19.2 cm, 16.3 cm, 12.5 cm, 12.8 cm and 11.4 cm. Find its standard deviation.

Find the standard deviation of the following data 7, 4, 8, 10, 11. Add 3 to all the values then find the standard deviation for the new values.

If P(A) = 0.37, P(B).= 0.42, P(A∩B) = 0.09 then find P(AUB).

If A and B are two events such P(A) = \(\frac{1}{4}\), P(B) = \(\frac{1}{2}\) and P(A and B) = \(\frac{1}{8}\), find (i) P(A or B) (ii) P(not A and not B)

Find the variance and standard deviation of the wages of 9 workers given below: Rs.310, Rs.290, Rs.320, Rs.280, Rs.300, Rs.290, Rs.320, Rs.310, Rs.280.