Suppose the ages at retirement for workers in the U. S. are normally distributed with an unknown population mean and standard deviation. If a random sample of 43 retirees is taken to estimate the mean retirement age, what t-score should be used to find a 80% confidence interval estimate for the population mean?

1.302

Step-by-step explanation:

The sample used was 43 retirees, so n=43. To find the degrees of freedom:

df=n−1=43−1=42

The confidence level is given in the scenario: 80%. So,

α=1−CL=1−0.8=0.2

But we want to use the value for α2, which is 0.22=0.1. Using the table, we need to find the row for 42 degrees of freedom, and the column for t0.1. So, the t-score we would use to find the 80% confidence interval is 1.302.

We could also use a calculator and input 1−α2=0.9 and the degrees of freedom into invT, in which case we would enter invT(0.9,42).

d. millimeters per hour.

step-by-step explanation:

we are given that,

carlo used a rain gauge to measure the amount of water his lawn is receiving from the sprinklers.

since, according to the options, we see that,

water cannot be measured by 'miles per hour', 'meters per second' and 'grams per seconds'.

we get that, the water can be measured by 'millimeters per hour'.

hence, the appropriate rate for describing the amount of water is 'millimeters per hour'.

so firstly, we need to isolate the y variables to be able to solve these inequalities. firstly, add 0.5x on both sides of the first inequality and subtract 1.5x on both sides of the second inequality:

now since the slope is positive for the first inequality, this means that the line going upwards belongs to the first inequality, and the line going downwards belongs to the second inequality.

next, since y ≥ in the first inequality, this means that the shaded region will be above the first inequality's line, thus shading regions a and b.

next, since y ≤ in the second inequality, this means that the shaded region is going to be below this line, thus shading regions a and c.

since both lines shade region a, this means that region a is the solution.

step-by-step explanation:

mark brainliest!