In an examination of purchasing patterns of shoppers, a sample of 36 shoppers revealed that they spent, on average, $50 per hour of shopping. Based on previous years, the population standard deviation is $4.80 per hour of shopping. Assuming that the amount spent per hour of shopping is normally distributed, calculate a 90% confidence interval.

the 90% confidence interval is ( 48.684  , 51.316  )

Step-by-step explanation:

Given that :

the sample size = 36

Sample Mean = 50

standard deviation = 4.80

The objective is to calculate a 90% confidence interval.

At 90% confidence interval ;

the level of significance = 1 - 0.9 = 0.1

The critical value for

= 1.645

The standard error S.E =

=

= 0.8

The Confidence interval level can be computed as:

For the lower limit :

=50 - 1.316

= 48.684

For the upper limit :

=50 + 1.316

= 51.316

Thus, the 90% confidence interval is ( 48.684  , 51.316  )

answer: i'm not sure

step-by-step explanation:

c.   x=2.4cm

step-by-step explanation:

similar triangles are triangles which have the same shape but not the same size. this means their angle measures are equal but their side lengths are not instead they are proportional. to solve, we will set up a proportion and solve.

a proportion is two equal ratios set equal to each other. we form the ratios by finding corresponding sides (sides which match to each other on both triangles by their position). out ratios will be one side of the small triangle over the corresponding side on the big triangle as shown below:

.

to solve the proportion, we'll cross multiply by multiplying numerator with denominator across the equal sign.