The mean monthly bill for a sample of households in a city is $70, with a standard deviation of $8.

using this data, let us assume that the number of households is 40

a. estimate the number of households whose monthly utility bills are between $54 and $86

b. in a sample of 20 additional households, about how many households would you expect to have monthly utility bills between $54 and $86.

a) 39

b) 58

Explanation:

Data provided in the question:

Mean = $70

Standard deviation, s = $8

Number of households, n = 40

Now,

a) number of households whose monthly utility bills are between $54 and $86

z score for $54 = [ 54 - 70 ] ÷ 8                  [ z score = [ X - mean ] ÷ s]

or

z score for $54 = -2

z score for $86 = [ 86 - 70 ] ÷ 8                  [ z score = [ X - mean ] ÷ s]

or

z score for $54 = 2

Therefore,

P(between $54 and $86) = P(z = 2) - P(z = -2)

= 0.9772498 - 0.0227501

= 0.9544997

Therefore,

number of households whose monthly utility bills are between $54 and $86

= P(between $54 and $86)  × n

= 0.9544997 × 40

= 38.18 ≈ 39

b) In a sample of 20 additional house i.e n' = 40 + 20 = 60

thus,

number of households whose monthly utility bills are between $54 and $86

= P(between $54 and $86)  × n'

= 0.9544997 × 60

= 57.27 ≈ 58

hi,

henry is an economist and wants to understand the relationship between inflation and consumer spending habits. for his research, he needs the consumer price index for 2014 and the inflation rate. based on the prices of goods given, what will he find to be the cpi and inflation rate for 2014? assume that a consumer’s basket for three consecutive years consists of the following:

you dont privide answer choices.

answer - 15% of a inflatation rate is 15% less in cpi