Spreadsheets: p-value with Excel

Tutoring stats, you deal with p-values. The tutor shows an Excel connection.

In my posts here and here I mention p-values.

Example: Using Excel, get a two-tailed p-value for z=2.4

Solution: Using symmetry, it’s best to get the cumulative z-probability for -2.4, then double it:

=2*normsdist(-2.4)

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.

Biology: what is a trophic level?

Tutoring biology, you come across the concept of trophic level. The tutor defines it.

In an ecosystem, a tropic level can be thought of as a level of energy or of consumption.

The organisms at trophic level 1 are called primary producers. By photosynthesis, they harvest energy from the sun to produce carbohydrates. Grass is a primary producer; in the ocean, phytoplankton is an example.

At trophic level 2 are the plant-eaters.

At trophic level 3 are predators (carnivores).

Source:

Mader, Sylvia S. Inquiry into Life, 9th ed. Toronto: McGraw-Hill, 2000.

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.

Lifestyle: symptomatic relief

More lifestyle self-tutoring: to take or not to take cold relief medication? The tutor offers perspective.

There’s a cold circulating; yesterday it hit me like a ton of bricks. Yet, I had to perform my duties.

Normally, I just tough out a cold, not taking anything. By 7pm last night, however, I’d had enough, so took some symptomatic relief.

The cold was so deeply entrenched, I didn’t feel better for about two and a half hours. Yet, by bedtime I felt much better, so went to sleep easily. In the middle of the night I woke up, still unfettered by the headache and congestion that had troubled me throughout the day. Sweat told me my fever had broken for real.

Had I not taken the symptomatic relief, I wouldn’t have slept so well; likely, my recovery may have been slower. However, there might be even a more important idea to consider.

The hopeless feeling that a cold can leave you with can be debilitating. I recall lying on the couch, wondering how I’d endure the next couple of days.

Once the symptoms had subsided, I regained a normal point of view. This morning, facing more sinus congestion, I took another dose. Over the past fifteen hours, I’ve taken much less than the directions allow, but it’s helped considerably.

I think I’ve changed my mind about cold medication. Taken within directed amounts, it can considerably improve a person’s function who would be struggling with a cold.

Yet, one must remember that, however good they feel after the medication quells the symptoms, they still have a cold: Rest and warmth are needed to truly beat it. Until the cold is gone, elective activities – like working out, for instance – should be traded for rest.

Such is my perspective, anyway.

If you, like so many others, struggle with this cold, best of luck to you:)

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.

Lifestyle: when to harvest apples

Lifestyle is continuous self-tutoring – for me, anyway. The tutor comments about when he chooses to pick apples from the tree.

When my first son was born, we planted him an apple tree. Without having to compete for sunlight, or space, it’s prospered over fifteen years. Today it’s heavily laden with apples, which I’m about to pick.

When to harvest the apples is often a question. I’ve read it’s best to wait until a few fall off, but for me that’s only one of three cues:

  1. A few apples fall off by themselves.
  2. Picking one, it tastes sweet.
  3. The first fall storm has come.

Our first fall storm was yesterday, of course: for me, therefore, the time has come to harvest the apples. I’m not recommending these guidelines, but they’re how I decide.

Source:

mygardengeek.com

wikihow.com

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.

Comp sci: asynchronous vs synchronous communication

Tutoring comp sci, you might explain asynchronous communication vs synchronous. The tutor describes them.

Asynchronous communication refers to modes in which the correspondents need not be engaged simultaneously. Email, text messaging, and comment boards facilitate asynchronous communication. In such contexts, the receivers respond at their convenience.

Synchronous communication requires the correspondents to be simultaneously engaged, waiting for incoming messages, reading them as soon as they arrive and responding directly. The motivation for waiting and responding immediately is to continue the stream of communication. A phone call or face-to-face conversation is synchronous communication.

Source:

stackoverflow.com

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.

English: what is a rebus?

Tutoring English, you discover new modes of communication. The tutor mentions rebus.

A rebus is a puzzle that suggests an idea partly with letters or symbols, but partly by placement or pictures.

Following my previous post about subtext, my little rebus example follows:

Do you understand the text?

Source: wikipedia

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.

English: subtext

Tutoring English, you know it has its own terms. The tutor brings up subtext.

Subtext refers to the point the author intends to convey to the reader. It’s not the literal meaning, necessarily, but rather the true meaning. A quick example follows:

A sign hung on the wall: Non-members please have papers ready.

The subtext of the sentence above is that non-members will face more hassle than members.

Source:

Barber, Katherine et al (editors). Oxford Canadian Dictionary of Current English. Don Mills: Oxford University Press, 2005.

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.

Music, Art: piano lessons

Tutoring, you notice different knowledge students bring from their backgrounds. The tutor reflects about piano lessons, including his own exposure to music as a child.

By my recollection, my family got a piano when I was about six. At first, we kids didn’t play it; my mother did. She had been a music teacher and knew lots of old show tunes, the music for which she purchased. From the dining room came those old tunes, hours each day, from then on. Often, she sang along. (That house had hardwood floors: I’m sure most musicians would proclaim that the acoustics were probably favourable.)

My mother and I have rarely had much in common, but I’ll admit that she always could play the piano. (Really, she wasn’t a bad singer, either.) I learned the piano because of her. Back then, my tastes didn’t point to show tunes. However, hearing, day in and day out, those songs by Gershwin, Cole Porter, and many others, was an education that, to quote Otto Harbach (lyricist of Smoke Gets in Your Eyes), “cannot be denied.”

My kids (12 and 15) are both in piano lessons. I’m not formally their teacher, but most days of the week I run their practice sessions, and I direct them through the summer. This past one I told them to learn some Gershwin–I guess you could say it goes back to my mother’s playing. They didn’t like Gershwin’s style at first, but my wife and I held the line; they’re doing well now with a couple of songs each.

My kids often don’t want to practice; ironically, they like performing. I’ve watched their progress since they started around 2010 – only seven years ago. What can happen in seven years is unbelievable, as any parent knows:) Moreover, I have no doubt that learning the piano has helped them with every other academic pursuit they’ve faced.

I studied the piano for seven years, some without even a teacher. When I finally gave it up, I didn’t know what value it might have given me. However, I didn’t know I’d be a parent, either. Playing the piano has become a family tradition.

I freely admit I’ve made terrible mistakes as a parent. However, my conscience is clear about making my kids practice the piano, however much they’ve resented it sometimes.

Three interesting points to mention:

  1. My mother, as far as I recall, never made me practice the piano:)
  2. Putting our kids in piano lessons was my wife’s idea; she did it without telling me. Since then, though, I’ve been the enforcer of practicing.
  3. Somewhat ironically, my wife didn’t have piano lessons as a kid; rather, she learned the violin, which her father also plays.

Source:

wikipedia

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.

Calculus: the cooling constant of the casserole

Tutoring calculus or differential equations, Newton’s Law of Cooling will surface. The tutor looks at a real-life example.

In yesterday’s post I mention that a casserole dish taken out of the oven cooled from 177C to about 40C during one hour.

Newton’s Law of Cooling can be used to calculate the temp of a cooling object:

Tf = Tiekt

where

Tf = final temp

Ti = initial temp

k = the constant of cooling (if cooling, k will turn out negative)

t = time (usually in seconds)

For this case, we have t=3600 (3600s in one hour):

40 = 177ek3600

Dividing both sides by 177 gives

0.226=e3600k

Now we ln both sides:

ln0.226 = 3600k

Finally we divide by 3600:

-4.13×10-4 = k

Apparently the cooling constant of the casserole is -4.13×10-4.

Source:

Larson, Roland E. and Robert P. Hostetler. Calculus. Toronto: D.C. Heath and Company, 1989.

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.

Cooking: temp of a warm object

Cooking means constant self-tutoring. The tutor speculates about the actual temperature of a warm object.

Yesterday I took a glass casserole dish of mac and cheese from the oven. Its baking temp was 177C.

An hour later, most of the mac and cheese had been served from the dish. Moving it, I was surprised how warm it still was to the touch.

Yet, how warm was it? I didn’t have a convenient way of measuring, so I opened a browser tab and found rc.rynryder.com, whose members seem to agree that about 60C is dangerous to touch for more than a second or two.

The casserole dish wasn’t hot; rather, just surprisingly warm. I’d estimate it was about 40C.

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.