Answer:
Step-by-step explanation:
(5y+4+3x)(5y+4-3x) = (5y+4)² - (3x)²......(from the difference of 2 squares )
by identity : (a+b)(a-b) = a² - b²
in this exercice ; a = 5y+4 and b = 3x
Answer:

Step-by-step explanation:
the mean is given by:

In our case this is:

side note: the main difference between sample mean and population mean is in the 'context'. However, the method to calculate them is the same.
By context I mean: if this the items are taken from some larger category for example: the ages of a few 'students' from a 'class'. Here 'students' are the sample from a larger set that is 'class'. The mean of the 'few students' will be called sample mean. In contrast, if we take the mean of the ages of the whole class then this is called population mean. (population mean == mean of the whole set)
In our case we aren't told exactly where these numbers come from, is this the whole set or a sample from it, the lack of context allows us to assume that the mean can either be population mean or sample mean. So we can safely use any symbol
or
.
Answer:
For 99% of confidence interval is 67.5±1.3524
Step-by-step explanation:
Given:
Mean height =67.5 inches
Standard deviation:2.1 inches
Z at 99%.
No of samples 16.
To find:
confidence interval
Solution:
We have formula for confidence interval,
=mean ±Z*{standard deviation/sqrt(no.of observation)}
Now
Z=99%
has standard value as ,
Z=2.576
Confidence interval= mean±Z{standard deviation/sqrt(No. of samples)}
=67.5±2.57{(2.1/sqrt(16)}
=67.5±2.576(2.1/4)
=67.5±1.3524
Answer:
98 °
Step-by-step explanation:
We know that the sum of the angles in a triangle is 180. We also know that angle DAB is 122°, meaning that angle CAB is 180-122, which is 58°. We also know that angle CBA is 24 degrees. Therefore, angle x is just 180-(58+24), which is 98
Answer:
D. 165
Step-by-step explanation:
if A+n=180
75+90+n=180
165+n=180
n=180-165
n=15
A+n=180
A+15=180
A=180-15
A=165 (D)