Answer:
12) Between 40 and 64 = 0.815
13) Between 32 and 40 = 0.0235
14) Between 56 and 64 = 0.34
15) At most 56 = 0.515
16) At least 72 = 0.025
17) At most 64 = 0.855
Explanation:
To answer this, we will convert each of the values into their standardized form to make this easier.
The standardized score for any value is the value minus the mean then divided by the standard deviation.
z = (x - μ)/σ
x = Each value
μ = Mean = 56
σ = Standard deviation = 8
12) Between 40 and 64
For 40,
z = (x - μ)/σ = (40 - 56)/8 = (-16/8) = -2
For 64
z = (x - μ)/σ = (64 - 56)/8 = (8/8) = 1
So,
Between 40 and 64 = Between -2 and 1
From the curve, noting that the central point is the mean, with standard score of 0, the lines before it move in step of 1 standard deviation towards the negative side, that is, -1, -2, etc. And the lines before the central point move towards the positive side, that is, 1, 2, 3, etc.
So,
Between -2 and 1 = 0.135 + 0.34 + 0.34 = 0.815
13) Between 32 and 40
For 32,
z = (x - μ)/σ = (32 - 56)/8 = (-24/8) = -3
For 40,
z = (x - μ)/σ = (40 - 56)/8 = (-16/8) = -2
So,
Between 32 and 40 = Between -3 and -2 = 0.0235
14) Between 56 and 64
For 56,
z = (x - μ)/σ = (56 - 56)/8 = (0/8) = 0
For 64,
z = (x - μ)/σ = (64 - 56)/8 = (8/8) = 1
Between 56 and 64 = Between 0 and 1 = 0.34
15) At most 56
For 56,
z = (x - μ)/σ = (56 - 56)/8 = (0/8) = 0
At most 56 = At most 0 = 0.0015 + 0.0235 + 0.15 + 0.34 = 0.515
All the regions before z = 0)
16) At least 72
For 72,
z = (x - μ)/σ = (72 - 56)/8 = (16/8) = 2
At least 72 = At least 2 = 0.0235 + 0.0015 = 0.025
(All the regions from z = 2 to the end)
17) At most 64
For 64,
z = (x - μ)/σ = (64 - 56)/8 = (8/8) = 1
At most 64 = At most 1 = 0.0015 + 0.0235 + 0.15 + 0.34 + 0.34 = 0.855
(All the regions before z = 1)
Hope this Helps!!!
