Answer:
60°
Step-by-step explanation:
sum of interior angles of quadrilateral is 360°
∠C = 70°
∠D = 50°
∠C + ∠D = 120°
∴ ∠A + ∠B = 360° - 120° =240°
AO and BO bisect ∠A and ∠B
∠OAB + ∠OBA = 1/2 x ( ∠A + ∠B) = 120°
∠AOB = 180° - (∠OAB + ∠OBA) = 180° - 120° = 60°
Answer:
B. 97
Step-by-step explanation:
We have that to find our level, that is the subtraction of 1 by the confidence interval divided by 2. So:
Now, we have to find z in the Ztable as such z has a pvalue of .
So it is z with a pvalue of , so
Now, find M as such
In which is the standard deviation of the population and n is the size of the sample.
How many students should be sampled to be within 1 drink of the population mean with 95% probability?
This is n when
We know from preliminary studies that the standard deviation is around 5, so
We round up, so the correct answer is:
B. 97