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According to a Recent Survey, Women Chat on Their Mobile

question 71

Short Answer

According to a recent survey, women chat on their mobile phones more than do men (CNN.com, August 25, 2010). Irina wants to estimate the difference between the average chat time for female and male college students. She takes a random sample of 40 male students and 40 female students in her college. She finds that female students chatted for a sample average of 820 minutes per month with a sample standard deviation of 160 minutes. Male students, on the other hand, chatted for a sample average of 760 minutes per month with a sample standard deviation of 240 minutes. You may assume that the population variances are equal.
A) Construct a 95% confidence interval for the difference between the population means.
B) Can we conclude that average chat time is different between female and male college students with 95% confidence?

Understand the concept of standard costs and their role in budgeting and variance analysis.

Identify factors that can cause variances and understand their implications for management decision-making.

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Assess the impact of variances on performance evaluation systems.

Definitions:

Cash Register

A machine used in retail to calculate and record sales transactions and to store money.

Quarters

Refers to a fourth part or division of something, often used in the context of fiscal or academic periods.

Algebraic Expression

A mathematical phrase that can contain ordinary numbers, variables (like x or y) and operators (like add, subtract, multiply, and divide).

Tripled

Increased threefold or three times in quantity or value.