Use the Following Information to Answer the Question

question 31

Multiple Choice

Use the following information to answer the question. Many couples believe that it is getting too expensive to host an "average" wedding in the United States. According to the website HYPERLINK "http://www.costofwedding.com/" www.costofwedding.com, the average cost of a wedding in the U.S. in 2009 was $24,066. Recently, in a random sample of 40 weddings in the U.S. it was found that the average cost of a wedding was $23,224, with a standard deviation of $2,903. On the basis of this, a 95% confidence interval for the mean cost of weddings in the U.S. is $22,296 to $24,152.
-For this description, which of the following does not describe a condition for a valid confidence interval?

• A)The sample distribution must be normally distributed in order to have a valid confidence interval. The problem does not describe the distribution of the sample, so this condition is not met.
• B)The sample observations are independent because knowledge about the cost of any one wedding tells us nothing about the cost of any other wedding in the sample.
• C)The description states that the sample was randomly selected, so we can assume that the condition which states that the data must represent a random sample is satisfied.
• D)The sample size of 40 is large enough that knowledge about the population distribution is not necessary and the condition that the population be normally distributed or sample size be larger than 25 is satisfied.

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Definitions:

dB

A unit of measurement that indicates the relative loudness of sounds in terms of the logarithmic scale, with higher numbers representing louder sounds.

Amplitude

Stimulus intensity; in audition, roughly equivalent to loudness, graphed by the increasing height of a sound wave.

Loudness

Loudness is the subjective perception of the intensity of sound, often measured in decibels, influencing how sound is experienced.

Frequency

The number of occurrences of a repeating event per unit of time, often used in the context of waves or cycles.