Answer:
The approximate 90% confidence interval is;
70,244 to 70,732
Step-by-step explanation:
Here, we want to calculate the approximate 90% C.I for the situation
Mathematically;
CI = mean ± (z * SD)/√n
From the question;
mean = 70,438
SD = 645.3
n = 30
we can get z from the CI table
90% CI is same as; 1.645 z-score
So , substituting these values;
CI = 70,438 ± ( 1.645 * 645.3)/√30
CI = 70,438 ± 194
So the CI = 70,438 -194 to 70,438 + 194
= 70,244 to 70,732
Answer:
120 students did Jada survey
Step-by-step explanation:
*<em> Lets explain how to solve the problem</em>
- The results of Jada survey are shown in this circle graph
# Communication tools Text messages 5/12
# Phone 1/5
# Emails 1/20
# Other messaging apps 1/3
- A total of 50 students said they favored text messages to
communicate with friends
- We need to find the total number of the students in Jada survey
- <em>Assume that the total number of the students in the survey is </em><em>x</em>
∵ The Communication tools Text messages expressed by a
fraction 5/12 of the circle graph
∵ The total of 50 students said they favored text messages to
communicate with friends
- That means The fraction 
of x equivalent to 50
∴ 
- Multiply both sides by 12
∴ 5x = 600
- Divide both sides by 5
∴ x = 120
∵ x represents the number of the students in Jada survey
∴ 120 students did Jada survey
Answer:
it is 500
Step-by-step explanation:
is five hundred .1 in khan academy though which is weird
Answer:
-tan80°
Step-by-step explanation:
4) You know slope-intercept form is y=mx+b. So using these two given points, you can find the slope!
(-8,5) (-3,10) [Use the y1-y2 over x1-x2 formula to solve for slope]
10 - 5 5
--------- = ----- = 1
-3-(-8) 5
Hurray! You got a slope of one. Now substitute this back into your original equation:
y=mx+b --> y=1x+b
Next, we find what our "b" is, or what our y-intercept is:
Using one of the previous points given, substitute them into the new equation:
[I used the point (-3, 10) ]
y=1x+b
10=1(-3)+b SUBSTITUTE
10=-3+b MULTIPLY
10=-3+b
+3 +3 ADD
----------
13=b SIMPLIFY
So, now we have our y-intercept. Use this and plug it into the equation:
y=1x+b --> y=1x+13
y=1x+13 is our final answer.
5) So for perpendicular lines, your slope will be the opposite reciprocal of the original slope. (Ex: Slope is 2, but perpendicular slope is -1/2)
We have the equation y= 3x-1, so find the reciprocal slope!
--> y=-1/3x-1
Good! Now we take our given point, (9, -4) and plug it into the new equation:
y=-1/3x-1
-4=-1/3(9)+b SUBSTITUTE and revert "-1" to "b", for we are trying to find the y- -4=-3+b intercept of our perpendicular equation.
+3 +3 ADD
--------
-1=b SIMPLIFY
So, our final answer is y=-1/3x+(-1)
6) I don't know, sorry! :(
