Computer use.
A random sample of 197 12th-grade students from across the United States was surveyed, and it was observed that these students spent an average of 23.5 hours on the computer per week, with a standard deviation of 8.7 hours. If we plan to use these data to construct a 99% confident interval, the margin of error will be approximately.

(a.) 0.07
(b.) 0.62
(c.) 1.6
(d.) 8.7

Answer:

The margin of error will be approximately =

(c.) 1.6

Step-by-step explanation:

Sample of 12th-grade students = 197

Average hours spent on computer per week = 23.5 hours

Total hours spent = 4,625 (197 * 23.5) hours

Standard deviation = 8.7 hours

Confidence interval = 99%

Square root of sample size = [tex]\sqrt{x}[/tex] = 14.04

Standard deviation/square root of sample size = 8.7/14.04 = 0.6196

Z value at 99% confidence = 2.58

Margin of error = 0.6196 * 2.58

= 1.59857

= 1.6

This question can be determined by the  concept of standard deviation. The margin of 1.6 error will be approximately.

Given:

Random sample of 12th-grade students = 197

Average hours spent on computer per week = 23.5 hours

Therefore,

Total hours spent by 12th grade students  = [tex]\bold{(197 \times23.5=4629.5)hours}[/tex]  

Standard deviation = 8.7 hours (Given)

Confidence Interval =99% (Given)

Square root of  random sample size =  = 14.04

[tex]\bold{\dfrac{Standard\: deviation}{Square\: root\: of\: sample\: size} =\dfrac{8.7}{14.04 } = 0.6196}[/tex]

Therefore,

Z value at 99% confidence = 2.58

Margin of error = [tex]0.6196 \times2.58[/tex]  

                          = 1.59857 error

                          = 1.6 error

Thus, the correct option is (c) 1.6 error.

For further details, please refer this link:

https://brainly.com/question/13905583

Which expression is equivalent to -4 - 9?
A. 4 + 9
B. 4 - 9
C. -4 + (-9)
D. -4 + 9

Please help 30 points plus brainlyist who does first

Determine which expressions can be simplified further, and which cannot. Sort the expressions into the correct
category
2x + 3y
Can Be Simplified
Cannot Be Simplified
x + x
4r +
7y + 1
4y + 4x
y + 2y

Please help.

Solve the System of Equations by Graphing

y=4

3x+4y=4

Write an expression to model the following situation: A submarine was 32 m below sea level. It descended 28 more meters.

What is its new position below sea level?

32 + 28


32 – 28

–32 + 28

–32 – 28

Which expression is equivalent to 7 (x + 4)?

shasha worked in the garden for 3 hours and 40 minutes. she started at 8:30am. at what time did she stop?

round 8.193 to the nearest hundredth ​

Put brackets in the expression to make the following true. 4 - 7 - 8 + 6 = -17

Raju bought a book for Rs.35.65. He gave Rs.50 to the shopkeeper. How much money did he get back from the shopkeeper?​

If 1 and 2/3 cups of something fills 3/4 of a container, how many cups fill the container

f(x) = x + 2
Find f(-5)

Dustin decides to try selling whole-wheat muffins and bagels at his farm stand. He has $60 to spend on ingredients and 8 hours to prepare the muffins and bagels that he will sell on opening day. One dozen muffins costs $10 and takes 1 hour to make, while one dozen bagels costs $15 and takes 3 hours to make. Graph all possible combinations of the food that meets his goal. Which combination of bagels and muffins would meet Dustin's goal?
A. 4 dozen bagels and 3 dozen muffins
B. 2 dozen bagels and 6 dozen muffins
C. 3 dozen bagels and 1 dozen muffins
D. 1 dozen bagels and 3 dozen muffins

A brand of popcorn instructs users to microwave for 90–120 seconds on high. A student wonders what the ideal microwave time for popcorn might be and designs an experiment to find out. Bags of popcorn are placed in the microwave for different lengths of time: 90 seconds, 100 seconds, 110 seconds, and 120 seconds. Also, 2 types of microwaves with different power capacity will be used: 900 watts and 1,000 watts. At the end of the experiment, the number of unpopped kernels will be counted.

Using 3 lengths of time and 2 types of microwaves describes which part of the experiment?

the levels

the treatments

the response variable

the experimental units

CAN SOMEONE PLEASE HELP ME ON THE TOP ONE !!!!!!

Simplify
114
11
1
1112
01
114
0 114
0 11 12

7 4/10 greater than 7.421

If the area of the rectangle is(xA^3−4x^2−15x+21) and the width is (x-6), what is the length?

Complete the proof.
Given:
CM I AB
23 = 24
Prove:
AAMC ABMC
C
34
12
M
А
B
Ich

In ΔGHI, the measure of ∠I=90°, the measure of HI=47 Feet, and IG = 93 feet. Find the length of ∠G to the nearest degree​

Alex deposits $4,000 in a savings account that pays 5% interest, compounded semiannually. What is his balance after one year?

Karina pays $2.64 for pencil erasers. The erasers cost 0.11 each. how many erasers did she buy?

M=3 (-4,-7) PLease include steps!!( I will give brainliest)

find the value of x
help

Given a function described as equation y = 3x + 4, what is y when x is 1,2, and 3

Convert 70°F to degrees Celsius.
If necessary, round your answer to the nearest tenth of a degree.
Here are the formulas.
C=-(F-32)
9
F=-C +32
5
70 °F =
Х
?

What is J/-12 > 9??​

What is the slope of the line through
(
−
5
,
−
10
)
(−5,−10)left parenthesis, minus, 5, comma, minus, 10, right parenthesis and
(
−
1
,
5
)
(−1,5)left parenthesis, minus, 1, comma, 5, right parenthesis?


tysm

If a coconut has tree has 12 coconut on it if 25% of the coconuts fell to the ground how many fell

PLEASE HELP MEEEE!!!!! Marcos had 15 coins in nickels and quarters total amount of those coins is $2.25. How many quarters and dimes he has?

giving 30 points &’ brainliest to whoever can help w there two questions!!