3. (5 points) A company wishes to estimate the mean monthly electric bill. If the standard deviation is $400, how large a sample is required to estimate the mean electric bill to within $100

with 98% confidence?

9.304

Step-by-step explanation:

company wishes to estimate the mean monthly electric bill. If the standard

deviation is $400, how large a sample is required to estimate the mean electric bill to within $100

with 98% confidence?

Sample size, n = (Zcritical * σ) ÷ ME

σ = standard deviation ;

ME ≥ margin of error

α = 98% ; At 98% confidence level ;Zcritical = 2.326

n ≥ (2.326 * 400) / 100

n ≥ 930.4 / 100

n ≥ 9.304

n = 10

5x + 3y = - 4

step-by-step explanation:

the equation of a line in standard form is

ax + by = c ( a is a positive integer and b, c are integers )

express the line first of all in slope- intercept form

y = mx + c ( m is the slope and c the y-intercept )

to calculate m use the gradient formula

m = ( y₂ - y₁ ) / ( x₂ - x₁ )

with (x₁, y₁ ) = (7, - 3) and (x₂, y₂ ) = (4, - 8)

m = = -

y = - x + c ← is the partial equation

to find c substitute either of the 2 points into the partial equation

using (4, - 8 ), then

- 8 = - + c ⇒ c = -

y = - x - ← in slope-intercept form

multiply all terms by 3 to eliminate the fractions

3y = - 5x - 4 ( add 5x to both sides )

5x + 3y = - 4 ← in standard form

just pick what you think i need more time let me know if this

step-by-step explanation: