Answer: point estimate = 3.88
Margin of error = 0.63
Step-by-step explanation:
Confidence interval is written in the form,
(Point estimate - margin of error, Point estimate + margin of error)
The sample mean, x is the point estimate for the population mean. Let m represent the margin of error. Since the confidence interval is given as (3.25 , 4.51), it means that
x - m = 3.25
x + m = 4.51
Adding both equations, it becomes
2x = 7.76
x = 7.76/2
x = 3.88
Substituting x = 3.88 into x + m = 4.51, it becomes
3.88 + m = 4.51
m = 4.51 - 3.88
m = 0.63
Since x is the x-intercepts, that means x'=x" =6 or in other word the discriminante ( Δ = b² 4ac) =0. Answer is A
Amount of money received when x tickets are sold=$Y
Number of tickets sold=X
Slope of line= 
And , y- intercept = 8
Equation of line having slope m and y-intercept c is given by,
y = m x + c,
Expressing the above statement in terms of linear equation in two variable i.e a line is
Y =
X + 8
Answer:
Step-by-step explanation:
In the past, mean of age of employees
i.e. 
Recently sample was taken
n = sample size = 60
Mean of sample = 45
Std dev of sample s = 16

(Right tailed test)
Since only population std deviation is known we can use t test only
Std error = 
Mean difference = 45-40 =5
Test statistic t=
df = 60
p value =0.008739
Since p < 0.05 we reject null hypothesis
The mean age has increased.
Its C! Hope this helps and can you mark me as brainliest :))