In a study, we see that the average number of close confidants in a random sample of 2006 us adults is 2.2 with a standard deviation of 1.4 . if we want to estimate the number of close confidants with a margin of error within and with 90% confidence, how large a sample is needed? r

527

Step-by-step explanation:

Data provided in the question:

standard deviation, s = 1.4

Confidence level = 90%

Margin of error, E = 100% - 90% = 10% = 0.10

Now,

For 90% confidence level , the z value is = 1.64

also,

the relation for sample size and above data is given as

Sample size, n = [(z × s) ÷ E]²

or

n = [(1.64 × 1.4 ) ÷ 0.10]²

or

n = 527.16 ≈ 527

check the picture below.

well, the angle at the vertex d is clearly not a right-angle, let's check for the one at the vertex f which does look like,   however if it's indeed, that means ef is perpendicular to df, in which case their slopes will be negative reciprocal of each other.

so the negative reciprocal of the slope of ef is 1, however the slope of df is not 1, is 1/2, so nope, they're not perpendicular lines.

i dont know

step-by-step explanation: