Answer:
75 coloured pencils
Step-by-step explanation:
Let's say Jordon has x total pencils.
We know that 20% of these x pencils is 15, so we have:
20% * x = 15
Remember that % is just "out of 100", so 20% = 20/100 = 0.20. Then:
0.20x = 15
x = 15 / 0.20 = 75
Jordon has 75 coloured pencils.
<h3>
Answer:</h3><h3>cos(-t) = -4/9</h3><h3>sec(-t) = -9/4</h3>
Explanation:
Since cosine is an even function, we can say cos(-t) = cos(t) for all values of t. So this explains why cos(-t) = cos(t) = -4/9. No change happens.
To find the secant value, we apply the reciprocal. This is because sec = 1/cos. So that's how -4/9 flips to -9/4.
Answer:
The 90% confidence interval for the true mean natural gas bill for homes in the 19808 zip code area in February is between $292.48 and $331.32
Step-by-step explanation:
We have the standard deviation for the sample, which means that the t-distribution is used to solve this question.
The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So
df = 21 - 1 = 20
90% confidence interval
Now, we have to find a value of T, which is found looking at the t table, with 20 degrees of freedom(y-axis) and a confidence level of
. So we have T = 1.7247
The margin of error is:

In which s is the standard deviation of the sample and n is the size of the sample.
The lower end of the interval is the sample mean subtracted by M. So it is 311.9 - 19.42 = $292.48
The upper end of the interval is the sample mean added to M. So it is 311.9 + 19.42 = $331.32
The 90% confidence interval for the true mean natural gas bill for homes in the 19808 zip code area in February is between $292.48 and $331.32
I’m confused. The answer is already given. It’s 0.
Explanation: A dice only has up to 6 sides, therefore it won’t be possible for it to reach the number 8.