Lesson 6.1
Lesson 6.2
100

Find the z critical values for an 85% level of confidence.

+/- 1.44

100

Calculate t critical values for a 98% confidence interval and sample size of 39.

+/- 2.429

200
Calculate the confidence interval is the mean = 23.98 and E = 1.03

(22.95, 25.01)

200

Use the interval (127.88, 146.24) to find the margin of error. 

E = 9.18

300

Calculate margin of error  n = 50 and s = 4.36 with 95% confidence.

E = 1.209

300

In a random sample of 18 gameboys, the mean repair cost was $68 with a standard deviation of $2.41. Use a t-distribution to calculate the margin of error for a 92% confidence interval. 

E = 1.058

400

A random sample of 35 CTA students were selected. Their mean walk time to school is 2.14 minutes and a standard deviation of 0.17 minutes. Construct a 90% confidence interval to estimate the mean time of all CTA students.

(2.093, 2.187)

400
In a random sample of 20 CDs, the mean number of songs on them is 112 songs with a standard deviation of 18.362. Construct an 88% confidence interval for the t-distribution. 

(105.316, 118.684)

500

28 students in Ms. Smith's class of 40 students had a test score mean of 75% with a standard deviation of 6.7%. Construct a 92% confidence interval. 

(72.784, 77.216)

500

In a random sample of 25 people, the mean height was 163.2 cm with a standard deviation of 36.1 cm. Assume the population is normally distributed and use a t-distribution to construct a 94.3% confidence interval.

(148.77, 177.63)

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