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Sección: Teorema Central del Límite¿Cuál de las siguientes afirmaciones sobre la distribución de la media muestral, de acuerdo con el Teorema Central del Límite, es correcta?

Sección: Teorema Central del LímitePara muestras aleatorias de n = 40 llamadas, ¿cuál es el error estándar de la media muestral del tiempo de atención? Use σ ≈ 2.043.

Sección: Pruebas de hipótesis: proporción y dos muestrasSe contrasta si la tasa de resolución supera el estándar institucional de 80%: H₀: p = 0.80 frente a H₁: p ≠ 0.80, mediante una prueba z para una proporción. Al 5%, ¿cuál es la decisión y conclusión correctas?

Listening 3 (4 points)   Question: What year is the student?

Sección: Intervalos de confianzaConstruya un intervalo de confianza del 95% para la proporción de llamadas resueltas usando aproximación normal. ¿Cuál es el intervalo?

A professor wants to estimate the percentage of students who pass a stat class. Based on the previous experience, the professor guesses that about 80% will pass the class. How many students must be sampled to estimate the true population proportion within 5% with 95% confidence? 

Accounting department of an airline company claims that 2 out of 10 flights departing from a certain airport are delayed. Suppose you work for the company as a statistical consultant and want to see whether the true proportion of delayed flights is different from what they claim. You randomly selected 120 flights and recorded their flight status. Out of 120 sampled flights, 18 flights were delayed. The p-value of the test is   

For the hypotheses

Students in an introductory chemistry class participate in a mid-semester survey. They were asked whether having recitation classes better prepare them for the course. Their opinions were coded as “0” if the answer was No, “1” if the answer was Somewhat helpful, and “2” if the answer was Yes. This variable is:   

A vending machine sells bottles of coke, diet coke, lemonade, sweet tea, and water.  (a) How many different selections are there for a purchase of 10 bottles, assuming there are more than 10 bottles of each type?Answer: [A] selections (b) If the machine shows that there are only two bottles of coke left for sale (where there are more than 10 bottles of each of the others), how many different selections are there for a purchase of 10 bottles?Answer: [B] selections