Q1) Following frequency distribution reports electricity cost for sample of 50 two-bedroom apartments in Albuquerque, new Mexico in the month of May last year.
|
Electricity cost
|
Frequency
|
|
$80 upto $100
|
3
|
|
100 to 120
|
8
|
|
120 to 140
|
12
|
|
140 to 160
|
16
|
|
160 to 180
|
7
|
|
180 to 200
|
4
|
|
Total
|
50
|
i) Evaluate the mean cost.
ii) Evaluate the standard deviation.
iii) Use empirical Rule to evaluate proportion of costs within 2 standards deviations of mean. Write down these limits.