5. An online music streaming company, iTunez, charges Alex $8.99 each month for unlimited

The life in hours of a thermocouple used in a furnace is known to be approximately normally distributed, with standard deviation

Effectus [21]

Answer:

62 is the minimum sample size needed

Step-by-step explanation:

We know that the population is approximately normally distributed so we will use a z-score for 95% confidence, which is 1.96. We are given the population standard deviation of σ = 20, and are given that the error should be 5 or less hours. The fact that it gives us sample data is irrelevant since we are told the population is approximately normally distributed and are given the population standard deviation.

See the attached photo for the calculation of the minimum sample size

8 0

3 years ago

A biologist is studying the growth of a particular species of algae. She writes the fall inclusion to show the radius of the alg

horrorfan [7]

Answer:

Part A)

A reasonable domain to plot the growth function is:

$0\leq d \leq 12$

Part B)

The y-intercept represents that when the biologist started her study, the radius of the algae was five millimeters.

Part C)

The average rate of change from d = 4 to d = 11 was about 0.11. This means that from the 4th day to the 11th, the radius of the algae grew, on average, at a rate of 0.11 mm per day.

Step-by-step explanation:

The radius of the algae f(d) in millimeters after d days is given by the function:

$f(d)=5(1.02)^d$

Part A)

We know that the radius of the algae was approximately 6.34 mm when the biologist concluded her study. To find the reasonable domain, we can substitute 6.34 for f(d) and solve for d. Therefore:

$6.34=5(1.02)^d$

Divide both sides by five:

$(1.02)^d=1.268$

Take the log of both sides with base 1.02:

$\displaystyle d=\log_{1.02}1.268$

Using the Change of Base Property, evaluate for d:

$\displaystyle d=\frac{\log 1.268}{\log 1.02}=11.9903...\approx 12$

So, the biologist concluded her study after 12 days.

Therefore, a reasonable domain to plot the growth function is:

$0\leq d\leq 12$

Part 2)

The y-intercept of the function is when d = 0. Find the y-intercept:

$f(0)=5(1.02)^{(0)}=5(1)=5$

Since d represent the amount of days after the study had begun, the y-intercept represents the radius of the algae on the initial day.

So, when the biologist started her study, the radius of the algae was five millimeters.

Part 3)

To find the average rate of change for a nonlinear function, we find the slope between the two endpoints on the interval.

We want to find the average rate of change of f(d) from d = 4 to d = 11.

Find the endpoints:

$f(4)=5.4121...\text{ and } f(11)=6.2168...$

And find the slope between them:

$\displaystyle m=\frac{f(11)-f(4)}{11-4}=0.1149...\approx 0.11$

Since f(d) measures millimeters and d measures days, this tells us that, on average, the radius of the algae grew by about 0.11 mm per day from the 4th day to the 11th day.

5 0

3 years ago

PLEASE HELP !! ILL GIVE BRAINLIEST *EXTRA 40 POINTS* DONT SKIP :(( .!

velikii [3]

Answer:

maybe the second?

Step-by-step explanation:

7 0

3 years ago

In 1992, there were approximately 141 million births and 49 million deaths worldwide. What was the

Serhud [2]

Answer:

The population increased by 92 million.

Step-by-step explanation:

141 - 49 = 92

3 0

3 years ago

What relationship between two variables can be concluded from this statement?

Trava [24]

Performance of school students is associated with watching television

8 0

4 years ago

Read 2 more answers