In a survey, 24 people were asked how much they spent on their child's last birthday gift. The results were roughly bell-shaped with a mean of $31 and standard deviation of $6. Construct a confidence interval at a 80% confidence level.

29.4≤μ≤32.6

Step-by-step explanation:

The datas given from the questions are as shown:

Number of people n = 24

Mean xbar= $31

Standard deviation σ = $6

Confidence Interval formula is expressed as:

CI = xbar ± Z(σ/√n)

Z value for 80% confidence interval is 1.282

Substituting the values into the Confidence Interval formula will give;

CI = 31 ± 1.282{6/√24}

CI = 31 ± 1.282(1.225)

CI = 31 ± 1.57045

CI = 31+1.57045 and 31-1.57045

CI = (29.42955, 32.57045)

CI = (29.4, 32.6) to 1dp

The confidence interval will be within the range 29.4≤μ≤32.6

answer set (b) 0.5, 3/4 80% is in order from least to greatest.  

step-by-step explanation:

in order to compare rational numbers to each other, it is much easier if they are in the same form.   typically, the best form in which to evaluate rational numbers is in decimals.   in order to convert a percent to a decimal, you would divide the given percentage by 100.   you can also accomplish the conversion by moving the decimal point over two places to the left.   for example, the decimal value of 80% is 80/100, or 0.8.   in order to convert a fraction to a decimal, you need to divide the numerator by the denominator.   for example, 3/4 is 0.75.   so, for choice (b) 0.5 3/4 (0.75), 80% (0.8) is the only choice in which the numbers are in order from least to greatest.  

answer:   2 multiplied by x =24

step-by-step explanation: