Answer:

Step-by-step explanation:
The firm tests 75 parts, and finds that 0.25 of them are notusable
n = 75
x = 0.25 \times 75 = 18.75≈19



Confidence level = 95%
So, Z_\alpha at 95% = 1.96
Formula of confidence interval of one sample proportion:


Confidence interval 
Answer:
B
Step-by-step explanation:
The graph (although it doesn't show it) is making points at every 20 (dollars) mark and also lines up to each hour mark, meaning that for every hour, Tanya makes 20 dollars.
Answer:
x ≤ 31/3
Step-by-step explanation: