Find the 13th term of the arithmetic sequence -3x+7, -5x+3, -7x-1, ...
1 answer:
Answer:
a₁₃ = - 27x - 41
Step-by-step explanation:
The nth term of an arithmetic sequence is
= a₁ + (n - 1)d
where a₁ is the first term and d the common difference
Here a₁ = - 3x + 7
d = a₂ - a₁ = - 5x + 3 - (- 3x + 7)
= - 5x + 3 + 3x - 7
= - 2x - 4
Then
a₁₃ = - 3x + 7 + 12(- 2x - 4)
= - 3x + 7 - 24x - 48
= - 27x - 41
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Step-by-step explanation:
Assuming the data is as shown, restaurant X has a mean service time of 180.56, with a standard deviation of 62.6.
The standard error is SE = s/√n = 62.6/√50 = 8.85.
At 95% confidence, the critical value is z = 1.960.
Therefore, the confidence interval is:
180.56 ± 1.960 × 8.85
180.56 ± 17.35
(163, 198)
Restaurant Y has a mean service time of 152.96, with a standard deviation of 49.2.
The standard error is SE = s/√n = 49.2/√50 = 6.96.
At 95% confidence, the critical value is z = 1.960.
Therefore, the confidence interval is:
152.96 ± 1.960 × 6.96
152.96 ± 13.64
(139, 167)
