Answer: (29.4, 32.6)
Step-by-step explanation:
From the question, we know that
Sample size (n) = 27
Sample mean (x) = $31
Sample standard deviation (s) = $3
We are to construct a 99% confidence interval interval for average amount spent on gift.
The formulae for constructing a 99% confidence interval for population mean is given as
u = x + tα/2 × s/√n...... For upper limit
u = x - tα/2 × s/√n...... For lower limit
tα/2 is the critical value for a 2 tailed test. This value of gotten from a t distribution table by checking the degree of freedom ( 27 - 1 = 26) against the level of significance ( 100% - 99% = 1%).
Hence tα/2 = 2.779
Let us substitute our parameters and solve
For lower limit
u = 31 - 2.779 × 3/√27
u = 31 - 2.779 ( 0.5773)
u = 31 - 1.6045
u = 29.4
For upper limit
u = 31 + 2.779 × 3/√27
u = 31 + 2.779 ( 0.5773)
u = 31 + 1.6045
u = 32.6
Hence the 99% confidence interval for population mean is given as 29.4, 32.6
Answer:
Step-by-step explanation:
12n>135+4.50n
12(15)>135+4.50(15)
180>135+67.50
180>202.50
False. They will not make a profit since the cost is 202.50 versus the selling price 180
Answer:
The solution set is {-1, 7}.
Step-by-step explanation:
X^2-6X=7
X^2 - 6X - 7 = 0
(X - 7)(X + 1) = 0
X = 7, -1.
Explanation
to solve this we need to translate into math terms, so
Step 1
a) let d represents the number of dimes
let n represents the number of nickles
so
re write the expressions
The number of nickels is three more than seven times the number of dimes in other words you have to add 7 to seven times the number of dimes to obtain the number of nickles
hence
therefore , the expression for the number of nickles is
I hope this helps you
