Answer:
Mean = 47
Median = 47.38
Standard Deviation = 12.73
Explanation:
Note: You wrote " 40 manufacturing companies, but the total number of companies you actually listed is 75, definitely you meant 75.
Let y represent the range of advertising expenditure, f represent the number of companies, x represent the midpoint of the range of advertising expenditure.
y f x fx fx²
$20 to under $30 9 25 225 5625
$30 to under $40 13 35 455 15925
$40 to under $50 21 45 945 42525
$50 to under $60 18 55 990 54450
$60 to under $70 14 65 910 59150
n = 75
Mean,
Standard Deviation:
Median:
Get the cumulative frequencies(cf)
y f cf
$20 to under $30 9 9
$30 to under $40 13 22
$40 to under $50 21 43
$50 to under $60 18 61
$60 to under $70 14 75
N = 75
Median = Size of (N/2)th item
Median = Size of (75/2)th item
Median = Size of (37.5)th item
The median class = 40 to under 50
Lower limit, L₁ = 40
Cumulative frequency, cf = 22
f = 21
Class Width, h = 10
Median =
Median =
Median = 47.38