Step-by-step explanation: The true mean of a set of data is between an interval of values with a percentage of precision, e.g., a <u>99% confidence interval</u> means we are 99% confident the true mean is between the lower and upper limits.

To find the interval, use

x± $z\frac{s}{\sqrt{n}}$

z is z-score related to the % of confidence level

In this case, a 99% confidence interval is 2.576

x is sample mean

Calculating:

$x=\frac{63+69+62+66}{4}$

x = 65

65± $2.576\frac{3.16}{\sqrt{4}}$

65±4.07

Confidence Interval: 60.93 < μ < 69.07

Meaning that we are 99% sure the population means is between 60.93 and 69.07.

7 0

2 years ago

At Ree Ski Center, the most people will pay for a neck warmer is $10. The manager of Ree Ski Center knows he needs a 30% markup

taurus [48]

Let $x$ be the most the manager can pay the suppliers.

Then, we know from the information given in the question that the manager needs a 30% markup based on cost.

Therefore, the guiding equation will be:

$x+\frac{30}{100}x\leq 10$

because $10 is the most people will pay for a neck warmer.

Thus, the above equation will become:

$x+0.3x\leq 10$

$1.3x\leq 10$

$x\leq \frac{10}{1.3}=7.69$

$\therefore x\leq 7.69$

Thus, the most a manager can pay the suppliers for neck warmers and still keep the selling price at $10 is $7.69

4 0

3 years ago

In a class of 27 students, 14 play an instrument and 16 play a sport. There are 6

antiseptic1488 [7]

Answer: 1/3

Step-by-step explanation:

6 + 16 + 14 - 27 = 1/3

6 0

11 months ago