Since in this case we are
only using the variance of the sample and not the variance of the real population,
therefore we use the t statistic. The formula for the confidence interval is:
<span>CI = X ± t * s / sqrt(n) ---> 1</span>
Where,
X = the sample mean = 84
t = the t score which is
obtained in the standard distribution tables at 95% confidence level
s = sample variance = 12.25
n = number of samples = 49
From the table at 95%
confidence interval and degrees of freedom of 48 (DOF = n -1), the value of t
is around:
t = 1.68
Therefore substituting the
given values to equation 1:
CI = 84 ± 1.68 * 12.25 /
sqrt(49)
CI = 84 ± 2.94
CI = 81.06, 86.94
<span>Therefore at 95% confidence
level, the scores is from 81 to 87.</span>
Answer:
see graph of y = 5x - 7
Step-by-step explanation:
If graphing is the task, you should rewrite the equation in a y = ax + b form. All straight lines can be described in this form, only the a and b determine which line it is.
Your equation 5x-y=7 has the 5x on the left side, so lets move it to the right. It will get a negative sign (this is the same as subtracting 5x like you did in your picture)
5x - y = 7
-y = 7 - 5x
Now we still have the -y which should be a +y. So we multiply left and right with -1 and get:
y = -7 + 5x
If we swap the -y and 5x (we can, because they are just an addition), we get:
y = 5x - 7
Now the equation is in its "normal" form. It's like the y = ax + b with a and b chosen as a=5 and b=-7.
The normal form is handy because you can immediately see the slope is 5 and the intersection with the y-axis is at y=-7.
Answer:
Step-by-step explanation:
(3/4)*(2/5)=6/20=3/10