Exercises 1–4: experiments
two studies are described below. one is an observational study, while the other is an experiment.
study a:
a new dog food, specially designed for older dogs, has been developed. a veterinarian wants to test this new food against another dog food currently on the market to see if it improves
dogs’ health. thirty older dogs were randomly assigned to either the "new" food group or the "current" food group. after they were fed either the "new" or "current" food for six months,
their improvement in health was rated.
study b:
the administration at a large school wanted to determine if there was a difference in the mean number of text messages sent by ninth-grade students and by eleventh-grade students
during a day. students in a random sample of 30 ninth-grade students were asked how many text messages they sent per day. students in another random sample of 30
eleventh-grade students were asked how many text messages they sent per day. the difference in the mean number of texts per day was determined.

depends on how many days you are talking about

step-by-step explanation:

the system of inequity is

step-by-step explanation:

from the given graph it is noticed that we have two related lines. one is solid and another is dashed.

if a line passing through two points, then the equation of line is

the solid line passing through the points (0,4) and (4,0).

the related equation of solid line is .

similarly, find the related equation of dashed line. the dashed liune passing through the points (0,0) and (3,1).

the related equation of dashed line is

from the given graph it is noticed that the point (0,1) lies on the shaded region, therefore the point (0,1) must be satisfied by the related equations.

check the related equations by the point (0,1).

this statement is true if the sign of inequality is < instead of equality. since it is an solid line therefore the sign of inequality will be . the required inequality is

similarly, check the second related equation.

it is a dashed line, so this statement is true if the sign of inequality is > . the required inequality is

c. y = 1/4 x + 5

step-by-step explanation:

first, put the equation of the line on the graph into slope-intercept form

(y = mx + b):   y = -4x + 8

second, a perpendicular line has to have "an opposite/reciprocal slope" to the original slope. so, find the "m" value in your original equation (it's -4, right? )

original slope: m = -4   perpendicular slope: change the sign to its opposite and find the reciprocal ("flip" the number)

new slope is now positive (b/c the original slope was negative 4), and it's 1/4 (not the original slope of 4 or 4/1)

step-by-step explanation:

what are the statements? and what do you mean by "216 2 1 6"?