Complete question :
The lifetimes of a certain type of calculator battery are normally distributed. The mean lifetime is 400 days, with a standard deviation of 50 days. For a sample of 6000 new batteries, determine how many batteries will last: 360 and 460 days
Answer:
0.67307
Step-by-step explanation:
Given that :
Mean, m = 400
Standard deviation, s = 50
Sample size, n = 6000
Obtain the standardized score :
Zscore =(x - m) / s
For X = 360
P(x < 360)
Zscore =(360 - 400) / 50
Zscore = - 40 / 50
Zscore = - 0.8
P(Z < - 0.8) = 0.21186
For X = 460
P(x < 460)
Zscore =(460 - 400) / 50
Zscore = 60 / 50
Zscore = 1.2
P(Z < 1.2) = 0.88493
P(Z < 1.2) - P(Z < - 0.8)
0.88493 - 0.21186
= 0.67307
Answer:
0.3520
Step-by-step explanation:
We have been given that the pulse rates among healthy adults are normally distributed with a mean of 80 beats/second and a standard deviation of 8 beats/second. We are asked to find the proportion of healthy adults have pulse rates that are more than 83 beats/sec.
First of all, we will find z-score corresponding to sample score of 83 as:
, where,
z = Z-score,
x = Sample score,
= Mean,
= Standard deviation.
Upon substituting our given values in z-score formula, we will get:

Now, we need to find the probability that a z-score is greater than 0.38.
Using formula
, we will get:

Using normal distribution table, we will get:



Therefore, 0.3520 of healthy adults have pulse rates that are more than 83 beats/sec.
Answer:
See attachment
Step-by-step explanation:
The negative in front flips it over the y axis
The +1 moves it left
Have a great day!!!
(Also can I please have Brainliest, I need it to level up!)
Answer:
160
Step-by-step explanation:
Answer:
90
Step-by-step explanation:
an obtuse angle is an angle from 90 - 180 degrees, so it would greater than 90 degrees