Answer:
Step-by-step explanation:
Let x = the age of the youngest child
Let x + 1 = the age of the middle child
Let x + 2 = the age of the oldest child
x + x + 1 + x + 2 = 39
3x + 3 = 39
3x = 36
x = 12 years
Answer:
D is the answer.
Step-by-step explanation:
You can see if a line is perpendicular by the slope. If the slope is COMPLETELY opposite from another by means of slope, the lines are perpendicular.
-1/4
4/1
...are opposite.
Answer:
-2
Step-by-step explanation:
The equation of the line is written in y=mx+c form, where m is the gradient and c is the y-intercept.
In this case, your m is a -2 and your c is a -3.
Hence the gradient of the line is -2.
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
