Step-by-step explanation:
The plumber's daily earnings have a mean of $145 per day with a standard deviation of
$16.50.
We want to find the probability that the plumber earns between $135 and
$175 on a given day, if the daily earnings follow a normal distribution.
That is we want to find P(135 <X<175).
Let us convert to z-scores using

This means that:

We simplify to get:

From the standard n normal distribution table,
P(z<1.82)=0.9656
P(z<-0.61)=0.2709
To find the area between the two z-scores, we subtract to obtain:
P(-0.61<z<1.82)=0.9656-0.2709=0.6947
This means that:

The correct choice is C.
Answer:
it is 150 is the answer
Step-by-step explanation:
Answer:
320
Step-by-step explanation:
4*80=320
Answer:
Ecological correlation
Step-by-step explanation:
According to a different source, the options that come with this question are:
- Ecological correlation
- Extrapolation
- Lurking variable
- Influential observation
Sarah should be careful about the use of an ecological correlation. An ecological correlation describes two variables that are group means, as opposed to a correlation between two variables that describe individuals. In this case, Sarah did pick 75 random students in each state. However, she then obtained the height and weight means for each state, and proceeded to compare these. Therefore, Sarah is not comparing individual values, but means. It is important to notice this, because correlations at a group level can be much higher than those at the individual level.