4. To fix the frequency boundaries of relatively high gain, 0.7 Amid was chosen to be at the cutoff levels. The corresponding frequencies, f1 and f2, are generally called ________. A) corner frequencies B) cutoff frequencies C) half-power frequencies D) All of the above A: wrong. B: wrong. C: wrong. D: This is the right answer.

A filter that attenuates high frequencies while passing low frequencies is called a（ ）. A: bandpass B: bandstop C: lowpass D: highpass

. Which of the following frequencies is as international distress and safety frequencies on MF for radio telephone? A: 2187.5 kHz B: 2174.5 kHz C: 2182kHz D: 2177. OkHz

The sum of the relative frequencies for all classes will always equal:

中国大学MOOC: Recombination frequencies can be calculated by

智慧职教: How are paired NBDP frequencies normally used?

The sum of frequencies for all classes will always equal 1. (<br/>)

频数分析应选择的菜单是（） A: Analyze→Descriptive Statistics→Frequencies B: Analyze→Descriptive Statistics→Descriptives C: Analyze→Multiple Response→Frequencies D: Analyze→Multiple Response→Define Sets

An open pipe of air supports standing waves at frequencies of 300 Hz and 400 Hz. There are no other frequencies between these two. What is the frequency of the second harmonic of this tube? A: 100 Hz B: 200 Hz C: 400 Hz D: 600 Hz

中国大学MOOC: One way to define _____ is any change in allelic frequencies within a population.