To solve for proportion we make use of the z statistic. The procedure is to solve for the value of the z score and then locate for the proportion using the standard distribution tables. The formula for z score is:

z = (X – μ) / σ

where X is the sample value, μ is the mean value and σ is the standard deviation

when X = 70

z1 = (70 – 100) / 15 = -2

Using the standard distribution tables, proportion is P1 = 0.0228

when X = 130

z2 = (130 – 100) /15 = 2

Using the standard distribution tables, proportion is P2 = 0.9772

Therefore the proportion between X of 70 and 130 is:

P (70<X<130) = P2 – P1

P (70<X<130) = 0.9772 - 0.0228

P (70<X<130) = 0.9544

Therefore 0.9544 or 95.44% of the test takers scored between 70 and 130.

6 0

4 years ago

You bought 50 shares of stock at $55 per share and sold them for $61 per share. The sale involves a broker’s commission of $0.30

malfutka [58]

Answer:

The profit made is;

b) $285)

Step-by-step explanation:

The given parameters are;

The number of shares bought, n = 50

The price each share is bought, CP = $55

The amount at which each share is sold, SP = $61

The amount the broker received per share, E = $0.30

Therefore, the amount of profit, 'P', is given as follows;

P = n × (SP - CP - E)

By substituting the values for the variables, we have;

P = 50 × (61 - 55 - 0.3) = 285

The amount made as profit, P = $285.00.

6 0

3 years ago